Version 0.96f-zpl

- Modified code queue to store only a few codes and reduced its memory usage
- Implemented M226 (GCode initiated Pause)
- Rewrote most of the Move::Spin call and implemented split moves for 5-point bed compensation
- Improved Pause/Resume/Reset feature and parts of the networking code
- Removed some more redundant code
- Last message is now stored in Flash (may be useful for debugging)
- Bug fix: M120+M121 now save and restore the last-known extruder positions
- Bug fix: Possible endless loop in the Network code
- Other minor changes

Thanks to dc42 for the following:
- Initializing arrays using ARRAY_INIT macro
- Fixed issue where the active aux GCodeBuffer could become overwritten
- Implemented PrintingAFile interface again in the GCodes class
- Implemented M305 'X' parameter to swap ADC channels on demand
- Added support for M20 S2 and M36