Changes made for compatibility with android gradle plugin 2.3.0 and Gradle 3.3, with Scala updated to 2.11.8.

[xingda920813]

Hi, saturday06.

I have made some changes to gradle-android-scala-plugin, for Gradle 3.0+ deleted useAnt option, which is deprecated in Gradle 2.x. Continue to use useAnt will prevent Gradle to compile, so I removed it and updated Gradle to 3.3.

I also updated Android Gradle Plugin to 2.3.0. From 2.2.0, it seems new version of the plugin only exists in jcenter, not in mavenCentral any more. So I changed the preferable repo to jcenter to retrieve new version of plugin.

Scala has been updated to 2.11.8, with some other dependencies updated.

I have run integTest on my local env and passed all the tests.