Added various enhancements, see comment

- Added option dottext to enable or disable the text added to the dot navigation
- Added option activecls to define the active item/dot class (including setting the active class on the slide too)
- Added option start to let the slider start at another slide than the first one
- Added option transition and added fade functionality, outsourced animation(s) to separate functions _.slide() and _.fade()
- Prevent plugin from starting multiple Intervals
- Some code cosmetics to make the overall coding-style more consistent (single quotes, spaces in if else statements etc.)

I guess as you're working on version 2.0, which looks awesome btw, you're not really gonna work/merge this stuff into the old version, but I thought I'd share anyway...the changes shouldn't break any existing behavior, but just did some quick tests...

thanks a lot for this awesome plugin and keep up the great work!