add CONTRIBUTING.md
[ubx] improve ubx parser and ubx_ucenter module

- configurable data output rate
- configurable baud rate (taken from GPS_BAUD variable)
- add support of double and float to ubx parser
- add option to configure RXM_RAW messages (on LEA-T versions)
[dox] add some doc for ubx_ucenter
make-release-tarball.sh executable
[conf] ardrone2_raw: remove wrong NPS_JSBSIM_MODEL

We are still missing a JSBSim model for a quadrotor in X configuration (like the ARDrone2).
The "simple_quad" model is for + configuration.

Now you will get an error starting the NPS sim
(JSBSim failed to open the configuration file: foo/paparazzi/conf/simulator/jsbsim/aircraft/ardrone2_raw.xml).
But IMHO that is better than NPS just not working for no obvious reason.
[docs] update url for styleguide in CONTRIBUTING.md
[mission] add status report for mission module
[board] by default apogee boards don't use luftboot
[mission] send 0 as dummy type in status instead of 255
[supervision] force color format to #rrrrggggbbbb
[ins] add new ins based on invariant filter

- experimental invariant filter for complet ins
- tested on fixed-wing only, but should work on rotorcraft as well
- generic vector and rung-kutta library
- fix alt init in utm local frame
- settable channel order on mag hmc58xx module
Merge remote-tracking branch 'paparazzi/master' into chibios
[libopencm3] update libopencm3 to be able to set FP_FLAGS
[libopencm3] update to latest master to fix compilation error
[fatfs] add fatfs as a submodule and remove patchs