Revert "Fix registerListener and flush bugs."

This reverts commit 4bdc37d315a6dbdcf2425e70423ec43d7b74e102.
Revert "Sensor batching APIs for review."

This reverts commit d405e0fc8274e8dc9ce8d6e084f6ad679fa6e6fa.

Conflicts:
	api/current.txt
Revert "Fix for build breakage. Remove documentation link to hidden registerListener API."

This reverts commit 1f519d46828f11413c70653ce5c31eba25b3f633.
Revert "Sensor batching. Implementation for registerListener(with batch support) and flush APIs."

This reverts commit b4c76b18a369d940f448bcc55d7245b6b30084dd.
Revert "Fix for build breakage. Correcting the documentatation link in Sensor.java. I added a wrong link {@link #SENSOR_TYPE_ROTATION_VECTOR} instead of {@link #TYPE_ROTATION_VECTOR}."

This reverts commit f0f4a831128c57acb52ce91f6d96a9f2b710c80f.
Revert "Adding new constants for STEP_DETECTOR, STEP_COUNTER and GEOMAGNETIC_ROTATION_VECTOR."

This reverts commit 4b628cb53dd84dae82db941d49ef10d58f22bf07.
Revert "Revert "Revert "be more robust with handling unknown sensors"""

This reverts commit 3c9c0918635143f373817fff1ce5131b995282cf.