2 subclasses of ResourceLoaderWikiModule implement a duplicate version of getFlip...

2 subclasses of ResourceLoaderWikiModule implement a duplicate version of getFlip. Move it up into ResourceLoaderWikiModule

(Almost looks like it could all go into ResourceLoaderModule... But that uses a different version, seemingly, the only one. 3 other subclasses of ResourceLoaderModule implement the same version of getFlip as is moved into a parent class here... Seems daft to have a different version in the base abstract class... Minor oversight?)

Some documentation