Added native metadata support.

Metadata.java:
Fixed typo 8k != 8092. The comment was correct though.

In Metadata.h, the new Metadata class is declared in the ns android::media
to limit the chances of conflict with other packages.

The MetadataType in MediaPlayerInterface is gone and moved to Metadata as
an inner typedef.

Similarly the SortedVector<MetadataType> instance have been replace by a
new type Metadata::Filter.

All the keys declared in the java counterpart are also in Metadata.h.

Metadata.cpp:
Contains the implementation of the native metadata packing.

There an associated change in the opencore package that should go in
at the same time as this one.
diff --git a/media/libmedia/Android.mk b/media/libmedia/Android.mk
index cdaab04..07c81f7 100644
--- a/media/libmedia/Android.mk
+++ b/media/libmedia/Android.mk
@@ -2,24 +2,25 @@
 include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES:= \
-	AudioTrack.cpp \
-	IAudioFlinger.cpp \
-	IAudioFlingerClient.cpp \
-	IAudioTrack.cpp \
-	IAudioRecord.cpp \
-	AudioRecord.cpp \
-	AudioSystem.cpp \
-	mediaplayer.cpp \
-	IMediaPlayerService.cpp \
-	IMediaPlayerClient.cpp \
-	IMediaPlayer.cpp \
-	IMediaRecorder.cpp \
-	mediarecorder.cpp \
-	IMediaMetadataRetriever.cpp \
-	mediametadataretriever.cpp \
-	ToneGenerator.cpp \
-	JetPlayer.cpp \
-        IOMX.cpp
+    AudioTrack.cpp \
+    IAudioFlinger.cpp \
+    IAudioFlingerClient.cpp \
+    IAudioTrack.cpp \
+    IAudioRecord.cpp \
+    AudioRecord.cpp \
+    AudioSystem.cpp \
+    mediaplayer.cpp \
+    IMediaPlayerService.cpp \
+    IMediaPlayerClient.cpp \
+    IMediaPlayer.cpp \
+    IMediaRecorder.cpp \
+    Metadata.cpp \
+    mediarecorder.cpp \
+    IMediaMetadataRetriever.cpp \
+    mediametadataretriever.cpp \
+    ToneGenerator.cpp \
+    JetPlayer.cpp \
+    IOMX.cpp
 
 LOCAL_SHARED_LIBRARIES := \
 	libui libcutils libutils libbinder libsonivox