SAConnection not supporting prepare statement method

[danigosa]

Hi,

we find the library very handy above all the fact that automagically compiles the queries, however we noticed (and it's kinda annoying) that connection from pool is not supporting prepare method. I think it is like 5 lines of code inside SAConnection at most, and would keep the library consistent and not having to do when preparing statements compile_queryby hand.

[nhumrich]

every fetch does a prepare for you. But sure, I understand your desire to call the prepare method yourself. Feel free to add a PR. Otherwise, it might be a little before I can get to this.