Fixed bad error reporting logic for server errors

* Previously if the server sent back a weird error we'd just shove the
  body of the response at the user and call it a day. Funny, but not
  at all ok.
Added vim and sublime to gitignore.
Fixed some more error reporting problems.

* Fixes galah-group/galah#356
Validation failure is now correctly reported.

* Fixes galah-group/galah#344
Added option to print out exception info.

* Suppressed by default.
* This is related to galah-group/galah#356