Implement plPagePatcher

Unlike older versions of Plasma, plPagePatcher is just a namespace in this
implementation. This changeset also fixes some minor issues that cropped
up. Nothing too major. Move along, move along.
Fix some mauled function names

Those got screwed up in the greate [U]Int(N)->stdint cleanups. Might as
well fix them.
Improve plPatchUtil's validation

Move validation code into plPagePatcher. Now, we check the hashes of the
files and each key's buffer. This will definitely help debug any patches
that don't validate correctly.