Introduce ChangeLineFormatter in the client

Change-Id: Ib03eb7395b0524cd27052b7e2305a85523170d7c
Split ChangeHandler::getPagesToUpdate into new class with tests

Change-Id: I86a78a1a275c7deb7a822e1188a1a04c9c37bcf5
Merge changes I86a78a1a,Ib03eb739

* changes:
  Split ChangeHandler::getPagesToUpdate into new class with tests
  Introduce ChangeLineFormatter in the client