Fix webrtc compilation errors for Chrome Win64

Mostly disabling warnings in the gyp files.

BUG=1348
BUG=http://crbug.com/166496
BUG=http://crbug.com/167187

Review URL: https://webrtc-codereview.appspot.com/1063011
Patch from Justin Schuh <jschuh@chromium.org>.

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@3423 4adac7df-926f-26a2-2b94-8c16560cd09d
9 files changed