This commit enables additional features for SAMD21 with external flash:
- Viper and native code support. On a relatively slow devices, viper and
native code can be helpful.
- Freeze the asyncio scripts and add the select module.
- Enable Framebuffer support.
- Enable UART flow control.
- Enable a few more features from the extra features set.
Drop onewire and asyncio support from SAMD21 firmware without external
flash, leaving a little bit more room for future extensions. Asyncio was
anyhow incomplete.
Signed-off-by: robert-hh <robert@hammelrath.com>
aea93a88f8