Summary:
This will allow us to more easily use objc-diff in other tools.
New script has two "modes":
- No arguments: clones and builds objc-diff
- -p: Echos path to the objc-diff binary and exits (produces no other output)
Reviewers: ajsecord, #mdc_ios_owners
Reviewed By: ajsecord, #mdc_ios_owners
Subscribers: ajsecord
Projects: #material_components_ios
Differential Revision: http://codereview.cc/D783