Rename ManiphestTransactionPro -> ManiphestTransaction
Summary: Ref T2217. Pro is the new standard.
Test Plan: Lots of grep, made a pile of Maniphest views/edits.
Reviewers: btrahan
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T2217
Differential Revision: https://secure.phabricator.com/D7093