Cleaning up jarjar rules, and adding support for keep and zap.
Review Request #3428 — Created Feb. 5, 2016 and submitted
|benjyw, dturner-tw, jsirois, patricklaw|
The shading subsystem had some extraneous indirection, which used to be necessary but now very much isn't. I also added support for defining `keep` and `zap` rules, which we now have some use-cases for internally.
Added unit and integration tests to test_shader.py, and manually tested the new keep/zap rules internally.
CI went green here: https://travis-ci.org/pantsbuild/pants/builds/107332277
Fix nits and a couple testing typos.
Revision 2 (+182 -141)