Finish 2020 milestone

[ianfixes]

Highlights from CHANGELOG.md

Fixed

• esp8266:huzzah options updated as per upstream

• See CHANGELOG.md for more

Issues Fixed

• Fixes esp8266:esp8266:huzzah: invalid option 'FlashSize' #254 - Huzzah / invalid option FlashSize
• Fixes Due and Zero appear not to support shiftIn()  #252 - shiftIn support
• Fixes pinMode() error: ‘_NOP’ was not declared in this scope #249 - pinMode and _NOP
• Fixes Default iteration of platforms in CI should respect library.properties "architecture" setting #246 - respect architecture= when iterating
• Fixes Failing unit test on NOP #258 - remove overzealous pinMode macro
• Fixes Error in Arduino-ci run because of typo in library.properties produces cryptic error #237 - scan library.properties for typos
• Fixes .arduino-ci.yml is case sensitive for platforms #261 - add information about platform names being case sensitive
• Fixes Arduino-CI is failing to find include file #262 - scan library.properties for typos