pop3_doing: don't call pop3_dophase_done() if already failed

... it also clobbered the 'result' return value so that it wouldn't
return the error back to the parent function properly, which broke test
809 when run with 'multi-always'.
Curl_conncache_foreach: allow callback to break loop

... and have it take a proper 'struct connectdata *' as first argument
test 1504 and 1505: same as 1502 but with different cleanup sequences
Curl_hash_clean: OOM handling fix
curl_multi_remove_handle: fix memory leak triggered with CURLOPT_RESOLVE
Enable tests 1503, 1504 and 1505
socklift.c: Added select_ws function to support Windows

WinSock select() does not support standard file descriptors,
it can only check SOCKETs. The following function is an attempt
to create a select() function with support for other handles.
socklift.c: Quick fix to re-add missing code
lib556: enable VERBOSE to ease debugging on failures
curl_multi_remove_handle: commit 0aabfd9963 follow-up
sockfilt.c: fix some compiler warnings
sockfilt.c: commit b44da5a82a follow-up
sockfilt.c: commit b44da5a82a follow-up 2
curl tool: renaming hugehelp files to tool_hugehelp
curl tool: rename hugehelp files to tool_hugehelp
darwinssl: Fixed inability to disable peer verification

... on Snow Leopard and Lion

Snow Leopard introduced the SSLSetSessionOption() function, but it
doesn't disable peer verification as expected on Snow Leopard or
Lion (it works as expected in Mountain Lion). So we now use sysctl()
to detect whether or not the user is using Snow Leopard or Lion,
and if that's the case, then we now use the deprecated
SSLSetEnableCertVerify() function instead to disable peer verification.
RELEASE-NOTES: synced with e3ed2b82e6
curl.1: extend the -X, --request description
imsp.c: Fixed usernames and passwords that contain escape characters

Fixed a problem with sending usernames and passwords that contain
backslash, quotation mark and space characters.
lib/*.h: use our standard naming scheme for header inclusion guards