R1:92f3ffd81185

Drive differential revision list with custom fields

Summary:
Build the revision list table out of custom fields instead of hard-coding it, so
installs can add all sorts of zany things to it.

NOTE: You may need to implement sortFieldsForRevisionList() if you have a custom
DifferentialFieldSelector, or some fields might show up out of order.

This implementation will preserve the expected behavior:

public function sortFieldsForRevisionList(array $fields) {
$default = new…