[vendor] Ensure that all cflags are properly quoted.

Before it looked like the `-isysroot \"#{sdk_path}\"` part of the cflags
would terminate the string passed to the `--cflags` option.

Now all the contents of the `--cflags` option is quoted using
single-quotes instead.
in case app.resource_dirs contain duplicated entries, don't freak out
[OSX] add app.codesign_for_release (default to true) which controls if we need to code-sign for build:release
Revert "fix where Boxed#new doesn't work for GLKKit structure."

This reverts commit ac89cf6b4bde5c8f7f27d61a84260418158e8242.

http://hipbyte.myjetbrains.com/youtrack/issue/RM-342
Because this patch causes a conflict between method's structure signature and bridgesupport's structure signature
[UIAutomation] Make the drag command actually send events again.

However, for the moment this only works with 1 touch at a time.
2.17