Merge pull request #1 from PSUdaemon/derivative_kick

Add derive on value method to remove derivative kick
Remove derive on error as an option.
go fmt
Merge pull request #3 from PSUdaemon/derivative_kick

Derivative kick
Merge branch 'master' into tuning_changes

Conflicts:
	pidctrl.go
Change GetPID() to just PID()
Fix tests
Merge branch 'derivative_kick_tests' into tuning_changes
Merge pull request #4 from PSUdaemon/derivative_kick_tests

Fix tests
Merge pull request #2 from PSUdaemon/tuning_changes

Tuning changes
Merge branch 'master' into reset_windup

Conflicts:
	pidctrl.go
	pidctrl_test.go
Make idiomatic by removing Get prefix.
go fmt