[thrift] gut Erlang exception handling

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
diff --git a/lib/erl/src/thrift_sup.erl b/lib/erl/src/thrift_sup.erl
index 8f6eaf7..ab3f80e 100644
--- a/lib/erl/src/thrift_sup.erl
+++ b/lib/erl/src/thrift_sup.erl
@@ -1,6 +1,6 @@
 %%% Copyright (c) 2007- Facebook
 %%% Distributed under the Thrift Software License
-%%% 
+%%%
 %%% See accompanying file LICENSE or visit the Thrift site at:
 %%% http://developers.facebook.com/thrift/
 
@@ -29,7 +29,7 @@
     Args = [SF, Port, Handler, Processor, ST, TF, PF],
 
     ThriftServer = {thrift_server, {?MODULE, thrift_start_link, Args},
-		    permanent, 2000, worker, ThriftModules},
+                    permanent, 2000, worker, ThriftModules},
 
     {ok, {{one_for_one, 10, 1}, [ThriftServer]}}.