Feature: Add RAMPS CNC Controller Board

improve sled handling

Always do st_synchronize() before G28

add missing endstop-bits
(Travis don't see that part of code)

- create sled pin definition
- G28 Works with sled

Serial wait

More thermal protection

replace some bools

Make some z probe and servo code tweaks

Correction traductions

this PR replaces some bools with one char. this will safe 3 bytes and should also be sometimes a little bit faster.