Summary: * move type field to tException from subclasses
* add backtrace to tException
* add oop:is_a
* on exit, wrap exceptions in {thrift_exception, E} ... otherwise can't distinguish e.g. exit:{{tBinProtException, {tException, ...}}, Stack} vs. exit:{tBinProtException, {tException, ...} -- I hate erlang
* all throws/exits to tException:throw which does the wrapping described above
Reviewed By: eletuchy
Test Plan: been using this code on my live server ^_^
Revert: OK
git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665350 13f79535-47bb-0310-9956-ffa450edef68