Fix dependency with library poject that has jar files in libs.

For Android Library Project that [only] provides jar files in 'libs' directory,
the plugin should:
1, Add the jars into classpath of projects.
2, Add the jars into the dex file list.

Also jars in libs for AARs.
Fix dependency with library poject that has jar files in libs.

For Android Library Project that [only] provides jar files in 'libs' directory,
the plugin should:
1, Add the jars into classpath of projects.
2, Add the jars into the dex file list.

Also jars in libs for AARs.