Clean up command print/return statements

Currently, the return string for command processing is a bit long and may not be entirely helpful (but maybe the full command should actually be returned for the log). Consider cleaning it up to be more concise.

At present, when an operation is requested (ex "run neopixeltest") and errors out, the full error string is returned. While this is helpful for development, it clutters the display when it returns to the web application. In an ideal situation, the full error message would be logged locally (see #9) and an abbreviated yet explanatory one would be returned to the response topic.

It could also be that we could get rid of logging this in the web app entirely. I'm a little biased towards keeping some amount of feedback because as a user I like to have some idea of why things aren't working.