Nuttx.py fixes: Python 2.7 support (required for gcc-arm-toolchain from Terry Guo), fixed int parsing, show mybt by name

Conflicts:
	mavlink/include/mavlink/v1.0

Debug/NuttX: small changes to make it work with the current stable branch. Debug/NuttX made existing code work with python3 in gdb. Added some new features

also fixed preceding mask calculation in show heaps

Conflicts:

	Debug/openocd.gdbinit
	Debug/px4fmu-v1-board.cfg

Note: We now use the version of stm32f4x that comes with openocd 0.7.0 or later

Note; only tested with gdb 7.6. Will definitely not work with the stock PX4 toolchain's gdb.

very useful for JTAG debugging

Don't try to print the idle stack usage (we need to fix it up before the code can be adapted to measure it).

Break out the task stack usage sniffer so we can use it on systems where the task layout has been shrunk (e.g. PX4IO)