Support dynamic options

[sebakerckhof]

Is your feature request related to a problem? Please describe.

Sortable allows us to change many options on the fly (e.g. change the group with Sortable.option('group', ...). However, this react binding only supports changing disabled on the fly in the componentDidUpdate method...

Describe the solution you'd like It would be useful if other options, like group, can also be set dynamically.

Describe alternatives you've considered Alternatively, if the component would give us a ref to the Sortable instance, we could do it ourselves.

[daviedR]

+1

A ref to the ReactSortable instance would be really useful.

[CasperVerswijvelt]

This commit implements dynamic options https://github.com/SortableJS/react-sortablejs/commit/64c17c85b72ce4618ee014f0e2053d6e3e1cb60b