Release 1.6.0 - Bugfixes, new Adafruit board support, CI

• Try to mount Pico drive if not already present during sketch upload (#175)
• Docs: clarify pin assignments for i2c (#173)
• Two board variant definitions and a high speed SPI transfer function (#172)
• Add baud rate to main Serial.begin() (#170)
• Add TinyUSB usage note. (#168)
• CI for style, compilation checks (#166 #163 #159)
• Add quasi-sane abs() implementation to Arduino.h (#157)
• Fix debug level "Wire" compile error (#151)
• Ignore non-UTF8 chars in UF2 upload (#148)

Release 1.5.1 - New USB stack, Adafruit boards, compatibility

• Fix over/underclock support (#147)
• Add Adafruit ItsyBitsy and QTPy RP2040 (#144)
• Port Adafruit_TinyUSB_Arduino lib (#127)
• Add defs for compatibility (#142)
• Add -DBOARD_NAME="{build.board}" (#136)
• Add time support (time, gettimeofday, etc.) (#138)

Release 1.5.0 - New USB stack, Adafruit boards, compatibility

• Add Adafruit ItsyBitsy and QTPy RP2040 (#144)
• Port Adafruit_TinyUSB_Arduino lib (#127)
• Add defs for compatibility (#142)
• Add -DBOARD_NAME="{build.board}" (#136)
• Add time support (time, gettimeofday, etc.) (#138)

Release 1.4.0 - Massive memory/flash savings

• Massively reduce generated code and RAM size (#137)

Blink went from:

Sketch uses 215604 bytes (10%) of program storage space. Maximum is 2093056 bytes.
Global variables use 18152 bytes (6%) of dynamic memory, leaving 243992 bytes for local variables. Maximum is 262144 bytes.

To:

Sketch uses 56112 bytes (5%) of program storage space. Maximum is 1044480 bytes.
Global variables use 12152 bytes (4%) of dynamic memory, leaving 249992 bytes for local variables. Maximum is 262144 bytes.

For a savings of 155KB of flash and 6KB of RAM

Release 1.3.1 - USB Keyboard/Mouse and SPI bug fix

• Add support for shared USB Serial, Keyboard, Mouse (#132)
• Fix SPI default pinouts to SPI0, not SPI1 pins (#135)
• Add missing USB header (d'oh! I need a CI system)

Release 1.2.2 - Minor Cleanup

• Point people to READTHEDOCS for help, not GitHub
• Add stdlib_noniso.h to Arduino.h (#131)
• Added Printable.h in dir where it can be found
• Clean up directory organization, libpico build (#129)
• Clean up platform.txt, libpico build (#128)

Release 1.2.1 - Multicore/tone fixes

• Fix memory leak in tone/noTone calls (#125)
• Minor keyword and mutex fixes for multicore
• Additional multicore fixes, BOOTSEL and PIO (#123)

Release 1.2.0 - Muilticore support

Major update includes support for running setup and loop on core1.
See the updated documentation and Muilticore.ino for information.

• Look for UF2 drives in additional spots on Linux (#37)
• Add multicore support via setup1()/loop1()
• Update pico-sdk to 1.1.2
• Add HWSerial redirect
• PWM functions definitions added (#114)

Release 1.1.0 - Pinouts for Pico and Feather RP2040

• Set default pins for peripherals per datasheet (#103)

  Using the official Raspberry Pi Pico datasheet and the Adafruit Feather
  RP2040 schematic, set the default pins for peripherals to match.

• Miscellaneous multicore fixes, include paths

Release 1.0.3 - Arduino IDE 2.0 + Another Windows hotfix

Remove api from include path, add redirects

Can't have cores/rp2040/api in the include path because the Arduino API
dir has a "String.h" file.  On Windows, because it is case-insensitive
normally, this overrides the POSIX "string.h" header leading to bad
stuff.

Add manual redirect includes for commonly accessed headers in the
cores/rp2040 path instead.