Add batterystats & screenshot listener

See javadoc of the two listeners for usage.
Will add host side test for this feature later.
Bug: 36351803
Test: bit CollectorDeviceLibTest:android.device.collectors.ScreenshotListenerTest
Test: bit CollectorDeviceLibTest:android.device.collectors.BatteryStatsListenerTest
Test: Run instrumentation tests with listener enabled.
Add module collector-device-lib to Android.mk of the test package.
> m FrameworksCoreTests
> adb install -r -g \
${ANDROID_PRODUCT_OUT}/data/app/FrameworksCoreTests/FrameworksCoreTests.apk
> adb shell am instrument -w -r \
-e listener android.device.collectors.BatteryStatsListener \
-e class com.android.internal.os.BatteryStatsNoteTest \
com.android.frameworks.coretests/android.support.test.runner.AndroidJUnitRunner

Change-Id: I0bf59c695217991fc9995b38642776be4e854a96