travis: Add inital support

* Initial support for travis-ci.org
travis: Create build matrix for each target

* Build for each target
* Remove the `-j` flag due to each build VM only having "1.5" cores
Added initial version of JRPropo XBUS Mode B support.
travis: Use arm-none-eabi-gcc compiler

* Use the gcc-arm-none-eabi compiler.  This will cause Travis-CI to
  set the env variable `CC=gcc-arm-none-eabi` which would allow the
  Makefile to be simplified by not hardcoding `CC`
* "Travis CI VMs run on 1.5 virtual cores"
   http://docs.travis-ci.com/user/speeding-up-the-build/
   Use `-j2`
* Ask GCC to print it's version.  Travis-CI would do this automatically
  if there was a way to install gcc before `$CC --version` is
  automatically run.
Cleanup of code (whitespaces/defines etc). Added initial text for docs about XBus and its configurations.
Update Gps.md

made language more clear and consistent
Adding installation/backup/restore documentation.
Adding ATAIL support.

See https://github.com/multiwii/baseflight/pull/192
Cleanup for coding standard.
Changed name of define to better name.
Disable mixer configuration on CJMCU to save flash size.
Add MPU9150 mag support and mag autodetection.  Add AK8975 mag driver.

Note: not working on the sparky, MPU9150 needs passthough enabling but
when enabled the mag and gyro won't ack on the default addresses.  Needs
further investigation.
Removing BINARIES from the SOURCE repo.   Binaries are now attached to releases here: https://github.com/cleanflight/cleanflight/releases
Merge pull request #235 from geekaz01d/patch-2

Update Gps.md
Merge pull request #224 from GruffyPuffy/xbus

Added initial version of JRPropo XBUS Mode B support.
Merge pull request #223 from kylemanna/travis

travis: Add inital support for travis-ci.org
Adding IRC notifications to the TravisCI configuration.
Updating readme.
Fix being unable to configure mixer via GUI.
Cleanup sonar driver

* spend less time in interrupt handler.
* avoid pointer usage to prevent the inclination adjusted reading being
replaced by the interrupt handler's calculation.
* only calculate the actual distance based on the measurement when
required.