Copy vendor/images to build/resources/vendor/images

This allows custom skins to include images (for example, icon sets)
without the possibility of overwriting core paella assets.
Merge pull request #76 from harvard-dce/djcp-create-vendor-images

Copy vendor/images to build/resources/vendor/images
Document a git strategy for working with upstream
DCE customizations roll-up commit.
First stab at a cs50 theme
Styling, color, and icon improvements.
Use cs50 by default, disable all other extended profiles
Re-render when skins change
Add playback rate plugin
Toggle between two simplified layouts
Optimize video profile
Update git strategy RE the upstream git process refactor
Profile toggle / cycling support. Includes:

* The concept of fullscreen versus non-fullscreen profiles
* An event to switch to a fullscreen profile once, the first time a user
  switches resolution
* Multiple profiles that can be cycled through.
Move skin into vendor/skins
Style the frameControl plugin, subtle background gradient
Disable controls autohiding by setting the timeout to a huge value
Add additional video layouts for supported aspect ratios