JS reset option

[imrohan22]

For dynamic data, if data for all sets are 0, it gives error. After that even if we pass values greater than 0, venn is not drawing.
It works if we reset page and try again with data greater than 0.

Need facility to reset to default state.

[benfred]

I realized I hadn't pushed the lastest version to gh-pages so the examples were running an old version. This should be fixed by this commit: 88c63e0

This should work here now http://benfred.github.io/venn.js/examples/dynamic.html