Added more error handling

[nepda]

A few more messages

[mbonneau]

Hi @nepda ,

I made some changes after the PR from early and added some automated testing as well.

Is there any way that you can rebase these changes on the current release (0.1.1)?

[nepda]

You've changed the error handling from returning the error to the poster, to an "internal" exception. Can you explain why this is the better approach?
In my use case, I want to get informed from the "client" point of view.

[nepda]

I will fix the broken tests as soon as the error handling question is clarified ;)

[mbonneau]

In the test:
f9fbcb0#diff-8f3b5fbe3ee084c8a46e4bd7661d3297R24
I am just reusing the WampPost client as the Callee end also. So the test is structured like:

 +-----------+
 |HTTP Client|
 +-----------+
       ^
       |
     HTTP
       |
       v
  +--------+
  |WampPost|<---+
  +--------+    |
       ^      WAMP
       |        |
     WAMP       |
       |        |
       v        |
  +-------+     |
  |Thruway+<----+
  |Router |
  +-------+

With Thruway, you have to throw an exception to send an error back from the Callee side. Throwing the WampErrorException gives that end control over exactly what gets put into the error message.