Checkpoint work on MTP and PTP investigation.

This change includes work in progress on a C++ library for both host and device
MTP and PTP support.
Currently the makefile builds two test programs:

mtptest - a command line test program that implements a small subset of device side MTP.
Requires a kernel driver that has not been checked in yet.

ptptest - a host tool to test USB host support for detecting and communicating with
digital cameras over PTP.  Runs on Linux host.

Later this will be reformulated as a native library that will be used in the media process.

Change-Id: I81aab279975b600b59d99013ab97f9adf0b58da7
Signed-off-by: Mike Lockwood <lockwood@android.com>