Merge pull request adafruit#747 from dhalbert/reformat

add storage.erase_filesystem() to erase and reformat CIRCUITPY

Merge pull request adafruit#678 from tannewt/m0_no_timer_fix

Correct NO_TIMER index value for SAMD21.

Merge pull request adafruit#658 from tannewt/driver_page_update

Update driver links (for 2.x) including categories!

Merge pull request adafruit#650 from tannewt/merge_2x

Merge in commits from 2.x branch.

Merge pull request adafruit#580 from ladyada/pirkey

pIRKey tested w/ hardware

Merge pull request adafruit#541 from ladyada/itsybitsy_m0_fixes

Itsybitsy m0 fixes

Merge pull request adafruit#505 from dhalbert/2.2_update_cpx_frozen_libs

update CPX frozen modules to latest versions

Merge pull request adafruit#505 from dhalbert/2.2_update_cpx_frozen_libs

update CPX frozen modules to latest versions

Merge pull request adafruit#486 from dhalbert/2.x_lis3dh_3.0.0

update CPX frozen Adafruit_CircuitPython_LIS3DH to library version 3.0.0

Merge pull request adafruit#443 from dhalbert/3.0_spi

non-DMA SPI working; adding this now for testing; will continue with DMA