Ref T5568 - V0.
A new "MetaEngine" based on ConfigurationDrivenLintEngine, with "files" key that is a
map regex->replace, as in T5568#66793.
Updated PhutilTestEngine and NoseTestEngine, which are easiest for me to test; An "AnyBinTestEngine" (not
included here) would eventually grow to cover the "run this custom script" use-case.
Some names still need work...