0.7.0

• feat(pio): mostly done! #61 e350966
• test(pio): tests for the PIO instruction set 171a788
• test(pio): fix broken PIO assembler tests 47cc25f
• test(pio): fix SET PINS test (#65) 0b0ea10
• refactor: test driver code to test-utils directory 7b003bb

v0.6.5...v0.7.0