Added dynamic pager thumbnail creation

responsiveSlides now accepts thumb and thumbSrc options.
Thumb can be bg or img depending how thumbnail will be showed on pager.
Thub option requires pager to be set true.

Updated demo to reflect usage
Added dynamic pager thumbnail creation

responsiveSlides now accepts thumb and thumbSrc options.
Thumb can be bg or img depending how thumbnail will be showed on pager.
Thub option requires pager to be set true.

Updated demo to reflect usage
Merge branch 'master' of github.com:Glenf/ResponsiveSlides.js
Merge pull request #1 from Glenf/master

Thumbnails