Do some reorganizing

* Rename "function" classes to Main, e.g., Differ -> Differs::Main.
  This makes it easier to Ctrl-P for the right files (if you were
  looking for differ.rb you might get differs/something_else.rb).
* Change inspector classes so that what they return match what they're
  named after. That is, previously an Inspector actually was an
  InspectionTree object, and now the InspectionTree lives inside the
  Inspector.
* Remove the inspector Map, as well as the MapExtensions which are used
  by extension modules such as `super_diff/rspec`,
  `super_diff/active_record`, etc., in favor of the same registry
  mechanism that differs, operational sequencers, etc. use.
* Pluralize extension points in the Configuration object so that you can
  provide more than one custom differ, operational sequencer, etc., at a
  time.

This reorganization is in preparation for introducing new classes in the
future around eliding diff output.

Author: mcmire

Gemfile

@@ -5,6 +5,11 @@ source "https://rubygems.org"
 git_source(:github) { |repo_name| "https://github.com/#{repo_name}" }
 
 gem "appraisal"
+gem(
+  "attr_extras",
+  github: "mcmire/attr_extras",
+  branch: "pass-kwargs-in-explicit-static-facade",
+)
 gem "childprocess"
 gem "pry-byebug", platform: :mri
 gem "pry-nav", platform: :jruby

gemfiles/no_rails.gemfile

@@ -9,5 +9,6 @@ gem "pry-nav", platform: :jruby
 gem "rake"
 gem "rspec"
 gem "rubocop"
+gem "attr_extras", branch: "pass-kwargs-in-explicit-static-facade", git: "https://github.com/mcmire/attr_extras"
 
 gemspec path: "../"

gemfiles/no_rails.gemfile.lock

@@ -1,8 +1,14 @@
+GIT
+  remote: https://github.com/mcmire/attr_extras
+  revision: 6073a1d6c7ac2d1b7331a34a09ed2779c4fec83c
+  branch: pass-kwargs-in-explicit-static-facade
+  specs:
+    attr_extras (6.2.3)
+
 PATH
   remote: ..
   specs:
     super_diff (0.4.2)
-      attr_extras
       diff-lcs
       patience_diff
 
@@ -14,7 +20,6 @@ GEM
       rake
       thor (>= 0.14.0)
     ast (2.4.0)
-    attr_extras (6.2.3)
     byebug (11.1.3)
     childprocess (3.0.0)
     coderay (1.1.2)
@@ -64,6 +69,7 @@ PLATFORMS
 
 DEPENDENCIES
   appraisal
+  attr_extras!
   childprocess
   pry-byebug
   pry-nav

gemfiles/rails_5_0.gemfile

@@ -9,6 +9,7 @@ gem "pry-nav", platform: :jruby
 gem "rake"
 gem "rspec"
 gem "rubocop"
+gem "attr_extras", branch: "pass-kwargs-in-explicit-static-facade", git: "https://github.com/mcmire/attr_extras"
 gem "activerecord-jdbcsqlite3-adapter", platform: :jruby
 gem "jdbc-sqlite3", platform: :jruby
 gem "activerecord", "~> 5.0.0"

gemfiles/rails_5_0.gemfile.lock

@@ -1,8 +1,14 @@
+GIT
+  remote: https://github.com/mcmire/attr_extras
+  revision: 6073a1d6c7ac2d1b7331a34a09ed2779c4fec83c
+  branch: pass-kwargs-in-explicit-static-facade
+  specs:
+    attr_extras (6.2.3)
+
 PATH
   remote: ..
   specs:
     super_diff (0.4.2)
-      attr_extras
       diff-lcs
       patience_diff
 
@@ -26,7 +32,6 @@ GEM
       thor (>= 0.14.0)
     arel (7.1.4)
     ast (2.4.0)
-    attr_extras (6.2.3)
     byebug (11.1.3)
     childprocess (3.0.0)
     coderay (1.1.2)
@@ -86,6 +91,7 @@ DEPENDENCIES
   activerecord (~> 5.0.0)
   activerecord-jdbcsqlite3-adapter
   appraisal
+  attr_extras!
   childprocess
   jdbc-sqlite3
   pry-byebug

gemfiles/rails_5_1.gemfile

@@ -9,6 +9,7 @@ gem "pry-nav", platform: :jruby
 gem "rake"
 gem "rspec"
 gem "rubocop"
+gem "attr_extras", branch: "pass-kwargs-in-explicit-static-facade", git: "https://github.com/mcmire/attr_extras"
 gem "activerecord-jdbcsqlite3-adapter", platform: :jruby
 gem "jdbc-sqlite3", platform: :jruby
 gem "activerecord", "~> 5.1.0"

gemfiles/rails_5_1.gemfile.lock

@@ -1,8 +1,14 @@
+GIT
+  remote: https://github.com/mcmire/attr_extras
+  revision: 6073a1d6c7ac2d1b7331a34a09ed2779c4fec83c
+  branch: pass-kwargs-in-explicit-static-facade
+  specs:
+    attr_extras (6.2.3)
+
 PATH
   remote: ..
   specs:
     super_diff (0.4.2)
-      attr_extras
       diff-lcs
       patience_diff
 
@@ -26,7 +32,6 @@ GEM
       thor (>= 0.14.0)
     arel (8.0.0)
     ast (2.4.0)
-    attr_extras (6.2.3)
     byebug (11.1.3)
     childprocess (3.0.0)
     coderay (1.1.2)
@@ -86,6 +91,7 @@ DEPENDENCIES
   activerecord (~> 5.1.0)
   activerecord-jdbcsqlite3-adapter
   appraisal
+  attr_extras!
   childprocess
   jdbc-sqlite3
   pry-byebug

gemfiles/rails_5_2.gemfile

@@ -9,6 +9,7 @@ gem "pry-nav", platform: :jruby
 gem "rake"
 gem "rspec"
 gem "rubocop"
+gem "attr_extras", branch: "pass-kwargs-in-explicit-static-facade", git: "https://github.com/mcmire/attr_extras"
 gem "activerecord-jdbcsqlite3-adapter", platform: :jruby
 gem "jdbc-sqlite3", platform: :jruby
 gem "activerecord", "~> 5.2.0"

gemfiles/rails_5_2.gemfile.lock

@@ -1,8 +1,14 @@
+GIT
+  remote: https://github.com/mcmire/attr_extras
+  revision: 6073a1d6c7ac2d1b7331a34a09ed2779c4fec83c
+  branch: pass-kwargs-in-explicit-static-facade
+  specs:
+    attr_extras (6.2.3)
+
 PATH
   remote: ..
   specs:
     super_diff (0.4.2)
-      attr_extras
       diff-lcs
       patience_diff
 
@@ -26,7 +32,6 @@ GEM
       thor (>= 0.14.0)
     arel (9.0.0)
     ast (2.4.0)
-    attr_extras (6.2.3)
     byebug (11.1.3)
     childprocess (3.0.0)
     coderay (1.1.2)
@@ -86,6 +91,7 @@ DEPENDENCIES
   activerecord (~> 5.2.0)
   activerecord-jdbcsqlite3-adapter
   appraisal
+  attr_extras!
   childprocess
   jdbc-sqlite3
   pry-byebug

gemfiles/rails_6_0.gemfile

@@ -9,6 +9,7 @@ gem "pry-nav", platform: :jruby
 gem "rake"
 gem "rspec"
 gem "rubocop"
+gem "attr_extras", branch: "pass-kwargs-in-explicit-static-facade", git: "https://github.com/mcmire/attr_extras"
 gem "activerecord-jdbcsqlite3-adapter", platform: :jruby
 gem "jdbc-sqlite3", platform: :jruby
 gem "activerecord", "~> 6.0"