Removes extra headers
This commit provides Windows support

Code uses SSLIdentity which platform independent. Windows build
does not currently support encryption. Also Windows build links
to ipop-tap dll generated by mingw on Debian.
Windows build uses Schannel for XMPP security.

Since SChannel is native to Windows and does not currently support
DTLS, we only have a secure connection to XMPP server, but the
P2P connections are not encrypted, maybe in future we may look
into IPSec or NSS or OpenSSL for Win32.
Removes libjingle.gyp.diff