Split app name and version in Capabilities.

To enhance capability matching and to select the latest version of the app to test if the
app version is not provided by the users. This enhancement still retains the backward 
compatibility when users specified an AUT as "appName:appVersion".

Signed-off-by: Binh Vu <bvu@paypal.com>
Why would anyone send this? And why should the API allow people to do so? Why not just make the clients send:

   "aut": "io.selendroid.test:0.11.0"

or 

   "aut": "io.selendroid.test"

in which case the latest version will be selected automatically.