Extract formatRemainingTime()
Discard err from time.ParseDuration

We're passing in a string literal, so it's impossible to have any other outcome than the result we expect
Silently swallow parsing errors

The likelyhood of these occuring is low, and if it does, a program other than us modified the ~/.pomodoro file
Add make install
Add text to start command's output for clarity
Remote duplicate noTime var
Show emoji exclamation point when time has past
Show usage on incorrect command
Use start subcommand to start a timer
Add test for bad subcommands
Remove unused channels