preparations for unit measuring system

GcodeAFMotorV2.ino:

- changed VERSION to "3-alpha1"
- add defines  UnitOfMeasurement, SteppsPerUnit, DimensonX, DimensionY
- add output of unit system in [void where()]
- edit [void help()]

homecycle.ino:

- add some comments

line.ino

- add origin check
- changed #ifdef VERBOSE to regular if statement

oneStep.ino

- convert short notation of if statements to long version
- preparations for unit measuring system