Neo and Supertable fixes

Thanks @ttempleton for PR #91, helping to address issues with Neo.

Ability to takeover the default Neo block button (addressing issue #85 and potentially #84)

Fixed inline previews not showing in Neo fields (issue #92)
Added/fixed proper modal filtering for Neo fields, now the modal respects the children available to the block (issue #87)
Fixed bug with Neo block configuration crashing the previews (issue #88)
Fixed Supertable "matrix row" issue, where previews were incorrectly showing in nested Supertable rows for Matrix Fields (issue #96)
Fixed small bug where the page jumps when a preview is clicked in the modal

timmyomahony / craft-matrix-field-preview