Merge pull request #46 from bshelton229/0.6

Test suite boilerplate and Leaflet build update to 0.6
Update README.md

Add section on tests
Update README.md

Typo
Update README.md

Remove noise
Make Zoomslider._refresh update the state instead of just removing / readding the slider.
Merge branch 'master' of https://github.com/kartena/Leaflet.zoomslider