This changes almost all uses of "u-module" to just "module" for the
following built-in modules:
- binascii
- collections
- errno
- io
- json
- socket
- struct
- sys
- time
There are some remaining uses of "u-module" naming, for the cases where the
built-in module is extended in Python, eg `python-stdlib/os` uses `uos`.
Also, there are remaining uses of `utime` when non-standard (compared to
CPython) functions are used, like `utime.ticks_ms()`.
Signed-off-by: Damien George <damien@micropython.org>
After `reconnect()`, MQTTClient.socket is blocking by default, and
check_msg() can block. This commit aims to fix that behaviour by
reimplementing `check_msg()` for umqtt.robust and setting the socket to
non-blocking.
Fixes issue #192.
Damien George