There was one uninitialized value warning and two mismatched-sign
compare warnings. They both appear valid, the first occurring when MPD's
"format-stopped" contains {songPosition} or {queueLength} and the second
occurring when the clock's "timezones" array is more than 2 billion
items long (not likely, I admit). Fix both issues.
Currently, the bottom border on workspace buttons eats into the box size
and causes the text to sit higher than in other modules. This is ugly
when there are other modules (like the window title) right next to the
workspace module. To fix the issue, create the bottom border using an
inset box-shadow, which doesn't affect the box's content sizing.
Thomas Hebb