Summary:
Refactored plugins compilation script by splitting it into 3 scripts: 1) search plugins 2) compile plugins 3) watch plugins.
No functional changes in this review, it's just preparation for further changes.
Reviewed By: passy
Differential Revision: D20860443
fbshipit-source-id: 02900430199875574b992e597d09b82d0d7f32ef
