Add hardware_pwm() function to smoothie Pins
Add PID-loopback spindle speed control
Fix spindle PID D-term scaling
Fix mixed CRLF/LF line ends in score_cm3.h
Move systick initialization from main.cpp to Spindle.cpp
Fix SysTick_Config() so that one can set LOAD = SYSTICK_MAXCOUNT
Merge pull request #549 from PetteriAimonen/edge

Added spindle speed control module using PID feedback