SHAREVITALSIGNS: Initial commit for converting ShareVitalSigns project to use Gradle in Android Studio.

[ionathanch]

This is for issue #2. I managed to import just ShareVitalSigns into Android Studio, but it wouldn't autogenerate the Gradle stuff when I tried to import all of sharevitalsigns, so this is excluding the demo apps.
I've also had to raise the minSdkVersion from 10 to 14 in order for everything to work. android-support-v4.jar has been deleted because it's included as the dependency com.android.support:support-v4:26.0.0-alpha1. (This was the version it included automatically but the latest version is 26.1.0, can we upgrade to that?)

To build AARs and JARs:

1. Open the sharevitalsigns/ShareVitalSigns/ directory in Android Studio
2. Click File > Sync Project with Gradle Files
3. Open the Gradle sidebar on the right, or click View > Tool Windows > Gradle
4. In the sidebar, run the task ShareVitalSigns > ShareVitalSigns > Tasks > other > copyJar
5. The generated AAR and JAR files will be under sharevitalsigns/ShareVitalSigns/app/build/outputs/ in the aar/ and jar/ directories

Let me know if this works for you; you can try it out by checking out the androidstudio branch. I've tested it by copying the generated sharevitalsigns.jar to LNhealth/libraries/sharevitalsigns/sharevitalsigns.jar and building RRate as the provider and HybridPocketDoc as the receiver.