Refactor PatchTable and PatchScreen to use PatchValidator

This adds a new interface PatchValidator to PatchSetDetail.
PatchSetDetail now has two patchset traversal methods getNextPatch
and getPreviousPatch which skip patches based on the validator.

This refactoring also fixes the bug where when a file is skipped from
the preferences the link to the next file is not shown.

Change-Id: Ieeb9024600ed3e8a22329b5571dd4b81d050d7ea
1 file changed