Fix Android plugins not detected

Hi,
I’m developing some Android libraries and I'm using this plugin, but I have a problem.

gradle-android-plugin 0.13.x (released on this September) requires Gradle 2.1,
so I thought that coveralls-gradle-plugin v2.0.0 (supports Gradle 2.x) will work… but it doesn’t:

```
:
No source file found on the project: “myProject"
With coverage file: /path/to/myProject/build/outputs/reports/coverage/debug/report.xml
```

The cause is 82ad4e27.
This ignores Android plugins which are extending `BasePlugin` such as `AppPlugin` and `LibraryPlugin`.

```groovy
// This code correctly handles subclasses of BasePlugin
project.plugins.withType(BasePlugin) {

// This doesn’t… this only see the plugin class EQUALS to the BasePlugin
project.plugins.matching { it.class.name == "com.android.build.gradle.BasePlugin" }.all {
```

I made a fix for this.

For Android App/Library projects,
* gradle-android-plugin 0.12.x requires Gradle 1.10+ (which works well with coveralls-gradle-plugin v1.0.2),
* gradle-android-plugin 0.13.x requires Gradle 2.1+ (which works well with coveralls-gradle-plugin v2.0.0 + this fix).