Make event_remove_timer behave correctly with persistent timers
Unit test for event_remove_timer with EV_PERSIST.

Patch from dcicppin on sourceforge.
fix #73 and fix http_connection_fail_test to catch it
Merge remote-tracking branch 'origin/patches-2.0'
a program to print out the error strings for winsock errors
use FormatMessage for winsock errors

as discussed here:
http://archives.seul.org/libevent/users/Feb-2013/msg00004.html
make sure caching works, and we don't leak memory
use hashtable instead of linked list to cache winsock errors

as discussed here:
https://github.com/libevent/libevent/pull/41#issuecomment-13611817
test filling up the hash table a bit
Merge pull request #41 from ppelleti/winsock-errs

FormatMessage for winsock errors