Merge pull request #33 from moonlite/master

A full fix (including IE7-8 support) for Issue 24
Merge pull request #35 from moonlite/master

Small style fix where you could see the map between the border and the slider at the rounded corners.
Move to using submodules for the libraries.
Decided on not using this stylesheet (and also not wanting the burden of maintenance). Shout if you want this resurrected!
Indent with tabs
Update to reuse Leaflet 0.5 style classes
Fix IE6 again.
Make zoomsliderControl available through this.map
Experimental refactor.
Merge pull request #41 from ath0mas/patch-1

Make zoomsliderControl available through this.map
Now in a working and hopefully much more readable state (as in easier to follow).
- Better snap function
- Fix for disabling buttons when zoomlevels change
- Merge createButton and createZoomButton
- Only refresh when zoomlevels change.
Don't move the knob by fractions of pixels.
Now snapping works again.
Drop some now useless lines of code.
Oops, forgot to move the slider click method
Don't add knob before we have any real zoomlevels.
Add option for knob height. Would love to have this in css but it's a bit hard to calculate it when i want to.
Remove unused images.
I want UNIX line endings.