Add murphy support to audio session manager.

Add murphy support to audio session manager.

Enable audio policy preemtion with web apps
with configuration flags (possibly for different
verticals). First there are conditionals to spec
file to enable asm and Murphy support to be compiled
in. Main item is a separate function to enable asm
to work with Murphy. So you will have 3 choices:
no policy, asm or asm with Murphy. For example:
PC -> nothing defined, mobile -> asm defined,
IVI -> asm and asm with murphy defined.

Change-Id: I6b44335e17cef8957cc8cf6c8a6c63c778386a2c