Current monitoring on CC3D
First cut of allowing a 3POS switch on AUX3 to change rc rate.

rcRate is decreased when low, increased when HIGH and no change when the
switch is in the middle.

The rcRate ticks up/down at 0.01 every 500ms if the switch is left on.

If using a momentary switch and if you can toggle the switch between
middle and low or middle and high more frequently than 500ms then the
rate will be increased accordingly.  Similar to how a keyboard repeat
behaves.
Make the adjustment controls more sensitive by using a smaller 3POS
switch deadzone.
Makefile improvement
- root must be assigned when declared - with :=
- add autodependecy generation
Merge branch 'ledvinap-feature-makefile'
Trivial changes
- use inline functions for gpio (typesafe, no speed penalty)
- fix sortSerialPortFunctions (original was IMO broken)
- allow softserial port on sonar pin when FEATURE_SONAR is not enabled
- minor style changes and comments
quick fix
it is impossible to build some targets. This is quick fix to get it working again
Merge branch 'bugfix-targets' into feature-nvic
Centralized NVIC priorities
- NVIC priorities are moved to separate file, all values are replaced wit symbolic names. Priorities should be the same.
- tiny change in DMA initialization
Merge pull request #131 from ledvinap/bugfix-trivial

Trivial changes
Merge pull request #132 from ledvinap/bugfix-targets

quick fix
Update target identifier for MassiveF3.

Target identifiers should 4 characters long.
Merge pull request #133 from ledvinap/feature-nvic

Feature nvic
Merge pull request #128 from Pierre-A/cc3d-updates-1

Current monitoring on CC3D
Re-instate the original softserial workaround.

This will be investigated further after the softserial changes are
merged in.
Fix rc_controls_unittest to use midrc.
Update adjustmentConfig to include the adjustment timeout.
Use adjustment index rather than function to track state.
Seperate adjustment configuration from adjustment state.  Rename 'step'
parameter to 'delta' applying the adjustment.  Configure adjustment
states based on adjustment configuration for AUX3 and AUX4.
First cut of API documentation.

Note this is already out of date for current master branch.