Merge pull request #7 from porkbuns/master

Sync master
Merge branch 'master' of github.com:andrewhao/shmile
Save as .jpg instead of .jpeg for less confusion>
Adding StubCameraControl and associated tests. Invoke it with STUB_CAMERA=true
Merge pull request #18 from andrewhao/master

Finalizing the StubCameraControl
Renaming ImageTwiddler to ImageCompositor for clarity :)
Adding test
Updating README
Merge pull request #19 from andrewhao/master

Renaming ImageTwiddler to ImageCompositor for clarity.
Refactoring to move client code into subfolder.
Merge pull request #20 from andrewhao/master

Refactoring to move client code into subfolder.