audio policy: fix gapless playback when effects enabled

Do not allow offloading if one non offloadable effect is enabled. This prevents from
creating an offloaded track and tearing it down immediately after start when audioflinger
detects there is an active non offloadable effect.
Not doing so breaks gapless playback because AwesomePlayer will always be able to open
an offloaded track which will not be compatible with the previous PCM track and
Audiosink::open() will not recycle it.

Bug: 11181933.
Change-Id: I6d163806849d9093b9ec701ba8e8c1ccb658e3c8
Define and use DRC-specific volume curves when applicable

Add support for property defining whether a DRC on the speaker path
 is enabled and will boost soft sounds.
Define new volume curves with more attenuations than existing ones
 to compensate for DRC-induced boost on sonification sounds to
 provide a more "linear" control to the user over the applied volume.

Bug 11600699

Change-Id: If23dd097a8b9b5ebb61e75dd8512ff75e63ba899
Revert "audio: fix no audio playback issue in recorder app"

This reverts commit da18434d6f153ddaf9f7bf1df5cb732d8a47961f.
Merge branch 'android-4.4' into github