AudioFlinger files reorganization

Audioflinger.cpp and Audioflinger.h files must be split to
improve readability and maintainability.

This CL splits the files as follows:

AudioFlinger.cpp split into:
- AudioFlinger.cpp: implementation of IAudioflinger interface and global methods
- AFThreads.cpp: implementation of ThreadBase, PlaybackThread, MixerThread,
DuplicatingThread, DirectOutputThread and RecordThread.
- AFTracks.cpp: implementation of TrackBase, Track, TimedTrack, OutputTrack,
RecordTrack, TrackHandle and RecordHandle.
- AFEffects.cpp: implementation of EffectModule, EffectChain and EffectHandle.

AudioFlinger.h is modified by inline inclusion of header files containing
the declaration of complex inner classes:
- AFThreads.h: ThreadBase, PlaybackThread, MixerThread, DuplicatingThread,
DirectOutputThread and RecordThread
- AFEffects.h: EffectModule, EffectChain and EffectHandle

AFThreads.h includes the follownig headers inline:
- AFTrackBase.h: TrackBase
- AFPlaybackTracks: Track, TimedTrack, OutputTrack
- AFRecordTracks: RecordTrack

Change-Id: I512ebc3a51813ab7a4afccc9a538b18125165c4c
diff --git a/services/audioflinger/Android.mk b/services/audioflinger/Android.mk
index 4416b52..c4050b8 100644
--- a/services/audioflinger/Android.mk
+++ b/services/audioflinger/Android.mk
@@ -15,6 +15,9 @@
 
 LOCAL_SRC_FILES:=               \
     AudioFlinger.cpp            \
+    Threads.cpp                 \
+    Tracks.cpp                  \
+    Effects.cpp                 \
     AudioMixer.cpp.arm          \
     AudioResampler.cpp.arm      \
     AudioPolicyService.cpp      \