Read terminal color codes in daemon client on every run

[ilevkivskyi]

Currently terminal color codes are read once during daemon start-up, and then re-used on each run. So if the daemon is started in one environment (e.g. an IDE plugin) where colors are not available, and then run in another where they are available (e.g. a normal terminal), the colors stay disabled until the next daemon restart.

This is probably low priority because people don't often switch between running mypy daemon in a terminal and in IDE, and this doesn't cause mangled formatting.

[gvanrossum]

I often switch between terminal and PyCharm, actually.

[ilevkivskyi]

Me too :-) but I think we are outliers. We can see if people will complain about this.