Remove remaining cordova-android classes

Remove BuildHelper and PermissionHelper of cordova-android core dependency, from the src/main/java local folder of this project. These classes were moved to a gradle dependency since 0.0.2 tag

Fix gradle tools 3.0.1 not found

Added google() repository to get com.android.tools.build:gradle:3.0.1 dependency

Jitpack support

• Change cordova-android dependency local .aar to use jitpack into build.gradle file
• Release this tag to build from jitpack