* atmel-samd: Add support for internal filesystems.
This allows us to re-enable `os`. `random` is also enabled because
it solely depends on `os`.
Fixes#266. Its also a pre-requisite for #260.
* atmel-samd: Update SAMD51 linker script comments and MICROPY_MAX_STACK_USAGE enabling.
This saves a lot of RAM. Fixes#287.
Also fixed compilation of frozen_mpy.c to use supplied make rule rather than
builtin rule (supplied rule suppresses printing out the gcc command line).
* atmel-samd: Remove ASF3. This will break builds.
* atmel-samd: Add ASF4 for the SAMD21 and SAMD51.
* Introduce the supervisor concept to facilitate porting.
The supervisor is the code which runs individual MicroPython VMs. By
splitting it out we make it more consistent and easier to find.
This also adds very basic SAMD21 and SAMD51 support using the
supervisor. Only the REPL currently works.
This begins the work for #178.
Reworked frozen module support: clean up makefiles and handle multiple directories.
Modules to freeze are included as git submodules.
Add neopixel to circuitplayground express build.
Fixes#56
Dan Halbert
Scott Shawcroft
Scott Shawcroft