ENH: some minor stylistic cleanups
ENH: Merge of Andrey's master branch
ENH: re-order labels to better match workflow
ENH: clean up and fixed initialization of slider

After apply, set the value to maximum since that matches
what the label displays.
ENH: change the button from Apply to March

This is more consistent since other tools, like draw and threshold
use Apply to mean that the operation is complete, while here the
button means to perform the first phase.
Merge pull request #1 from pieper/master

some tweaks and cleanups