v0.7

Release Notes:

• USB: Fix end-of-stream detection on track writes
  • Writes of empty/unformatted tracks sometimes hung forever
• No Flux Area: Firmware automatically masters long NFAs during track writes
  • Generating no flux transitions does not read back as a NFA
• STM32F73xx: Initial support for new STM32 MCU
  • Two HEX files are included: Use Greaseweazle-F1-* for existing boards!
  • Single unified UPD file containing both firmware images