Use the new prebuilt-library support to wrap the ARM CMSIS DSP library, and update to the version shipped with CMSIS 3.0 r3p2

Hotfix: install the firmware .bin files as well as the .px4 bundles until we have a chance to fix the px4io uploader.

these new ioctls allow for the flight code to tell the IO board that
arming can proceed

New led status

HOTFIX: simplify symbol names going into the ROMFS object, hopefully this avoids inconsistent symbol naming on Windows.

Change the way modules are built so that object paths are relative and use vpath for locating sources (so source paths are also shorter).

Add some basic documentation for the build system files while we're at it.

Marko Pagott <p0rc0.jet@gmail.com>

Quad wide arm mixer

MD25 Motor Controller Driver

Hil press fix

Velocity based gain adjustment based on dynamic presssure