Remove unused-but-confusing duplicate GCDAsyncSocket.m from project

Both CocoaHTTPServer and WebSocket use GCDAsyncSocket, so there are two
copies of the source code in the tree, but we only build one of them
(obviously) so that should be the only one in the project.
Change SSL settings to TLSv1, to avoid SSLv3 POODLE vulnerability

Fixes #492