Add patch to fix webview's NSView on Mac.

1. Avoid capturing key event to menu.
https://github.com/atom/atom-shell/issues/170

2. Enable accepting first mouse event.
https://github.com/atom/atom-shell/issues/212
Add patch to suppress warning of CFAllocator.
Add patch to make iframe sandboxed by default.
Do not contain the Debug build in distribution.

It would saves a lot of time when uploading & downloading on a slow
network, and in the atom branch the debug build is not actually used
too.