[Android-tools-devel] Bug#819074: point gradle to plugins

[殷啟聰]

I have updated the package to 2.0.0 and also tweaked it a little bit:

  1. Install Maven artifacts into /usr/share/maven-repo
  2. Auto-generate POMs using Gradle

Thus, by adding Debian's maven-repo into the build scripts and change
the Android plugin's classpath version to either "2.0.0" or "debian",
it should be able to use the plugin.

Directly applying the plugin's ID is the new mechanism since Gradle
2.1. You do not need specify a repository location probably because
Gradle will connect to Gradle's servers and download the corresponding
artifacts. In order to use Debian's Gradle plugin, I'm afraid we still
need to specify the repository location and the full classpath of the
plugin.