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/btcore/Android.mk b/btcore/Android.mk
new file mode 100644
index 0000000..d530655
--- /dev/null
+++ b/btcore/Android.mk
@@ -0,0 +1,35 @@
+ ##############################################################################
+ #
+ #  Copyright (C) 2014 Google, Inc.
+ #
+ #  Licensed under the Apache License, Version 2.0 (the "License");
+ #  you may not use this file except in compliance with the License.
+ #  You may obtain a copy of the License at:
+ #
+ #  http://www.apache.org/licenses/LICENSE-2.0
+ #
+ #  Unless required by applicable law or agreed to in writing, software
+ #  distributed under the License is distributed on an "AS IS" BASIS,
+ #  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ #  See the License for the specific language governing permissions and
+ #  limitations under the License.
+ #
+ ##############################################################################
+
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+
+LOCAL_C_INCLUDES := \
+    $(LOCAL_PATH)/include
+
+LOCAL_SRC_FILES := \
+    src/bdaddr.c
+
+LOCAL_CFLAGS := -std=c99 $(bdroid_CFLAGS)
+LOCAL_MODULE := libbtcore
+LOCAL_MODULE_TAGS := optional
+LOCAL_SHARED_LIBRARIES := libc liblog
+LOCAL_MODULE_CLASS := STATIC_LIBRARIES
+
+include $(BUILD_STATIC_LIBRARY)