Simplify the MemoryDealer implementation

At some point the implementation became complicated because of
SurfaceFlinger's special needs, since we are now relying on gralloc
we can go back to much simpler MemoryDealer.

Removed HeapInterface and AllocatorInterface, since those don't need
to be paramterized anymore. Merged SimpleMemory and Allocation.
Made SimplisticAllocator non virtual.

Removed MemoryDealer flags (READ_ONLY, PAGE_ALIGNED)

Removed a lot of unneeded code.
diff --git a/libs/audioflinger/AudioFlinger.cpp b/libs/audioflinger/AudioFlinger.cpp
index cad420a..9d52882 100644
--- a/libs/audioflinger/AudioFlinger.cpp
+++ b/libs/audioflinger/AudioFlinger.cpp
@@ -2929,7 +2929,7 @@
 AudioFlinger::Client::Client(const sp<AudioFlinger>& audioFlinger, pid_t pid)
     :   RefBase(),
         mAudioFlinger(audioFlinger),
-        mMemoryDealer(new MemoryDealer(1024*1024)),
+        mMemoryDealer(new MemoryDealer(1024*1024, "AudioFlinger::Client")),
         mPid(pid)
 {
     // 1 MB of address space is good for 32 tracks, 8 buffers each, 4 KB/buffer