Homestyx hydra

R1:b6733e4a8643

Phame - move over post creation and edit to use an editor

Summary: This adds the bare minimum transaction set for editing posts. Fixes T7626 because now files will be correctly attached to phame posts on subsequent edits. Future work here should be adding transaction types like `TYPE_BLOG` for when posts are moved between blogs, `TYPE_VISIBILITY` for when posts are moved to published, etc. Nothing too tricky there but keeping this diff relatively small seems prudent.

Test Plan: made posts successfully.
Repository: R1 hydra
Commit Date: May 15 2015