Move all the examples from the talk directory into the webrtc examples directory.

Significant changes:

- move the libjingle_examples.gyp file into webrtc directory.
- rename talk/examples/android to webrtc/examples/androidapp to avoid name conflicts.
- update paths in talk/libjingle_tests.gyp to point to webrtc directory for Objective-C test.

BUG=
R=pthatcher@webrtc.org, tkchin@webrtc.org

Review URL: https://codereview.webrtc.org/1235563006 .

Cr-Commit-Position: refs/heads/master@{#9681}
213 files changed