Input during startup (especially while doing initial filesystem format)
ran the risk of filling up the task queue, preventing the start_lua task
from being queued, and hence NodeMCU would not start up that time.
* Initial version of gdbstub support
* Add DEBUG argument to Makefile to add more debug data and turn off -Os
* Add the output redirection handling
* Added documentation
* Cleaned up the english a bit
* Make gdboutput actually trap all the output
* Review comments
As with the last commit this rolls up the follwowing, but include the various
review comments on the PR.
- **Documentation changes**. I've added the taks FAQ as a stub new Extension
developer FAQ, and split the old FAQ into a Lua Developer FAQ and a Hardware
FAQ.
- **Tasking I/F**. New `app/task/Makefile`, `app/task/task.c`,
`app/include/task/task.h` and `app/Makefile` as per previous commit. Cascade
changes to `app/driver/uart.c`, `app/include/driver/uart.h`,
`app/user/user_main.c` and `app/modules/node.c`
- **GPIO Rework** to `app/modules/gpio.c` and `pin_map.[hc]`, `platform.[hc]`
in `app/platform`
- **Other Optimisations** Move the `platform_*_exists()` from
`app/platform/common.c` to static inline declarations in `platform.h` as
this generates faster, smaller code. Move lgc.a routines out of iram0.