1. add new example for A2DP and the related btif layer source code is ported
2. modification on osi_alarm_new API to support periodic timer
3. enable macro BTA_AR_INCLUDED, BTA_AV_INCLUDED, BTA_AV_SINK_INCLUDED
4. The A2DP example cannot work and can only be built successfuly
2.modified the thread.h file==> added the profile task event in it
3.modified bt_prf_task.c==>added the ready function in it
4.added the bt_prf_sys.h file
5.remove the profile_sys.h file
add bt_prf_task.h for defined the data & struct used for the profile task
add prodile_sys.h defined the profile system data used for profile task
modified component.mk