R1:f9b3e3360b0c

Continue moving classes with no callers in libphutil or Arcanist to Phabricator

Summary: Ref T13395. Move cache classes, syntax highlighters, other markup classes, and sprite sheets to Phabricator.

Test Plan: Attempted to find any callers for any of this stuff in libphutil or Arcanist and couldn't.

Maniphest Tasks: T13395

Differential Revision: https://secure.phabricator.com/D20977