[thrift] improved error logging and handling for Erlang bindings

[thrift] improved error logging and handling for Erlang bindings

Summary:
 * custom, extensible error logger -- show only relevant stuff
 * clean up of errors in developer-supplied handler module
   now gives sane error messages and doesn't crash whole server
   (introduces tApplicationException_HANDLER_ERROR)
 * more precise catch in tErlProcessor (exits gracefully only if
   transport closes)

Reviewed By: iproctor

Test Plan: tutorial works

Revert Plan: ok

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665186 13f79535-47bb-0310-9956-ffa450edef68