How To Exclude Specific Resources from an AAR Depedency?

EDIT:

Wrote advanced gradle task for you:

final List<String> exclusions = [];

Dependency.metaClass.exclude = { String[] currentExclusions ->
    currentExclusions.each {
        exclusions.add("${getGroup()}/${getName()}/${getVersion()}/${it}")
    }
    return thisObject
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile ('com.android.support:appcompat-v7:20.+')
    debugCompile ('com.squareup.leakcanary:leakcanary-android:1.3.1')
            .exclude("res/values-v21/values-v21.xml")
    releaseCompile ('com.squareup.leakcanary:leakcanary-android-no-op:1.3.1')
}

tasks.create("excludeTask") << {
    exclusions.each {
        File file = file("${buildDir}/intermediates/exploded-aar/${it}")
        println("Excluding file " + file)
        if (file.exists()) {
            file.delete();
        }
    }
}

tasks.whenTaskAdded({
    if (it.name.matches(/^process.*Resources$/)) {
        it.dependsOn excludeTask
    }
})

Now you can use method .exclude() on each dependency, providing into list of paths, you want to exclude from specified dependency.
Also, you can stack the .exclude() method calls.