Version 0.96a-zpl

Merged in most of RRP's new firmware features from 0.90-0.96:
- G32 runs /sys/bed.g if it exists (file doesn't have to be present with my fork)
- Ormerod 2 compatibility and different SD card images
- File print progress reported to web interface
- Duet v0.7 support (experimental)
- Network can be disabled (M552 S0)
INFO: The probe index of dc42's ultrasonic sensor had to change from 3 to 4 to stay compatible with RRP's firmware
Bug fix: Actual extruder positions are reported instead of internal ones used by the GCodes class
Improved code queuing and added more safety precautions
Updated README file to incorporate Network class and to mention my changes