Merge pull request #67 from SableRaf/master

camera_control_initialize() bug
Clarify GPL/BSD licensing - with/without AHRS algorithm
Fixed asserts that break in release (-NDEBUG) configuration
Link math library (-lm) in movetytouch example

Some users has linker errors for the sqrtf function.
Madgwick AHRS: Fix 64bit compatibility for invSqrt
Implement support for Sharp Shooter attachment

Based on the documentation by Alexander, Sebastian and Raphaël:
https://code.google.com/p/moveonpc/wiki/SharpShooter
Added sharpshooter Processing example