Introduce btcore, a low-level library to manipulate Bluetooth data types.

This change adds a single module to btcore: bdaddr. The bdaddr module
is reponsible for manipulating and working with Bluetooth addresses.
diff --git a/main/Android.mk b/main/Android.mk
index b4ff0df..b5c2b51 100644
--- a/main/Android.mk
+++ b/main/Android.mk
@@ -80,6 +80,7 @@
 	$(LOCAL_PATH)/../bta/include \
 	$(LOCAL_PATH)/../bta/sys \
 	$(LOCAL_PATH)/../bta/dm \
+	$(LOCAL_PATH)/../btcore/include \
 	$(LOCAL_PATH)/../osi/include \
 	$(LOCAL_PATH)/../gki/common \
 	$(LOCAL_PATH)/../gki/ulinux \
@@ -130,7 +131,8 @@
     libbt-brcm_stack \
     libbt-hci \
     libbt-utils \
-	libbt-qcom_sbc_decoder \
+    libbt-qcom_sbc_decoder \
+    libbtcore \
     libosi \
     libtinyxml2 \
     libbt-qcom_sbc_decoder