Removing ContentWindowInterface.

Change-Id: Ibb6a08e87f211ff9891f8d65790c0142b77a9cc3
Cleaning Content dimensions handling.

Change-Id: I2f8f9d8ada408a6c6a45f1f85e94531cdc578996
DisplayGroup classes use an MVC pattern.

Change-Id: Ic861ec9da35f66b51ec73323db99bf7d57029653
Improve the handling of ContentWindow Events.
Fix build with Poppler system packages.

Change-Id: Ia354d1040b1be76f84429df20558f056404d7121
Merge pull request #112 from rdumusc/contentwindowinterface

Merging ContentWindow with ContentWindowInterface