This change adds support to the PerforceParser for applying binary

files as part of changes. The most basic part of this is just the

implementation of the add/move/delete methods, but while working on this

I discovered that patching for Perforce was broken in a variety of ways:


We've traditionally relied on the patch command to handle opening

  the relevant files, and we still do, but it now opens and edits them

  in a way which requires running p4 reconcile. This command has been

  added to the end of the patch sequence.


apply_patch_for_empty_files would use a regex to pull out filenames

  from the diff that then got passed to p4 add or p4 delete, but

  that regex only stripped off a leading "//" and did not map filenames

  to client names. It seems like in some cases Perforce was clever

  enough to know that "depot/something/..." really meant

  "//depot/something/...", but that depended highly on what that depot

  was called and what the client mapping was set up to look like. I've

  changed it to map the depot filenames to local first.


apply_patch_for_empty_files was only being called in the case that

  the patch entirely failed to apply, meaning we had a change that

  comprised only empty files. Patches with a mix of empty and

  non-empty file changes would apply the non-empty ones and skip the

  rest. The fix for this issue is actually inside /r/14711, which

  reorganizes the top-level patching process to always call this method

  when needed.

Ran unit tests.
Applied a variety of patches that included mixes of empty, non-empty,

  and binary files.