Beta Version 1.2.00

This update addresses several problems reported by users and incorporates contributed fixes.

CAUTION: This is experimental software. Machine tools can be dangerous. Use at your own risk.

Changes in this release:

• Fix overflow that caused problems with large metric threads (thanks @hugosman65)
• Slow down the SPI bus from 250Kbps to 98Kbps
• Increase SPI timing delays slightly
• Aggressively filter bad key reads:
  • Require multiple, identical, consecutive reads before acting
  • Validate that only one key is pressed at a time (thanks @ngreenou)
  • Require all keys to be released between key presses
• Do not allow changes to mode or direction while the machine is in motion (thanks @C4fishfood)
• Add configuration option to ignore all keypresses when the machine is in motion (thanks @C4fishfood)