Group inline transactions in Pholio

Summary:
Fixes T2639 by grouping related transactions at display time, so all the inlines merge into a nice block.

(Note that this does not do anything about T2709 yet, so there's still no way to figure out where the inlines actually are.)

Test Plan: {F35262}

Reviewers: chad

Reviewed By: chad

CC: aran

Maniphest Tasks: T2639

Differential Revision: https://secure.phabricator.com/D5313