Added rounding factor and color selection about range-seek-bar HOT 4 OPEN

(sorry, not a defect of course, pls. change the type)

(and also I don't know whether these small changes qualify me for an @author 
entry, feel free to remove it if not ;-)

Hi Bachi,

sorry for the delay. Thanks for the enhancements! I totally agree with your 
color handling improvements, but have a question regarding the rounding factor. 
As I pointed out in a comment to issue #1, introducing step size (or your 
rounding factor) changes the behaviour of this widget in a way, so that the UI 
state (the screen position of the thumbs) do not represent its internal state 
(the selected values) anymore. This might confuse the user.

But maybe its only me thinking this is a problem. I'd love to have some voting 
mechanism on code.google.com. Anyone interested in commenting with "+1" or "-1" 
regarding this issue?

Well, what the rounding does is simply round the returned values, not the 
internal ones that are used for calculating the handle positions. So there's no 
change in the dragging smoothness. So, it's not really a step size, just a 
small convenience feature.

Cheers - Bachi