build: add script to create Android .mk files

The create_android_makefiles script will create .mk files for node and
all of its dependencies ready to be build using Android build system.

Signed-off-by: Robert Chiras <robert.chiras@intel.com>
PR-URL: https://github.com/nodejs/node/pull/5544


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>