Update build tools

Gradle and build tools updated to the newest versions.

TargetSdkVersion also bumped to 19.

New build tools required moving the example app to its own package:

```
Error:Execution failed for task ':example:processDebugResources'.
> Error: A library uses the same package as this project
You can temporarily disable this error with android.enforceUniquePackageName=false
However, this is temporary and will be enforced in 1.0
```