Enabled Digital Low Pass Filter (DLPF) on the MPU-6050

Still needs some testing
Set default Kp value to 9.0
New hex
https://github.com/arduino/Arduino/issues/1176 is now fixed
Added support for Spektrum satellite receiver

Still need to figure out how to detect if it's out of sync
Updated readies
Cleanup
Update submodules
Spektrum code can now bind with satellite receiver, detect if it starts in the middle of a frame and be used together with TOOLS
Forgot to use static_cast whenever casting int to char or uint8_t in serial code

Also updated some comments and other cleanup stuff
Increased delay while waiting for serial data

Sometimes it could miss some commands
Merge branch 'dev' into spektrum
Moved things around to make it easier to read
Highlight serial command properly in readme
Do not hardcode Spektrum channels
Beep long when EEPROM values are reset instead of two short beeps
Link to Youtube video on TKJ Electronics channel
Changed thumbnail
Merge branch 'master' into dev
Update submodules