Default MediaStyled notifications to CATEGORY_TRANSPORT
Default MediaStyled notifications to CATEGORY_TRANSPORT

This makes it easier to identify them later (e.g., for filtering).
The developer can always specify a different category if preferred.

Also fixed some javadoc related to setMediaSession()

Change-Id: I5f28514758218ff66fdbaa9fd37ccb19f12d4852

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base