Added filterOptions.fullWidth

[patorjk]

Closes #1334

Also updated documentation for filterOptions.

[coveralls]

Coverage decreased (-0.06%) to 76.432% when pulling b39b860 on filterFullWidth into 07427cd on master.

[wdh2100]

const cols = (column.filterOptions && column.filterOptions.fullWidth) === true ? 2 : 1;

Good feature. but, I see a lot of duplicated code.

[patorjk]

It could probably be optimized some, I'll leave it as is for now though. Ideally, the component render methods could be re-used for something like what's done here - #1120. That feature is pretty cool but it duplicates this file, which would just lead to headaches (I would have had to edit two files for this PR).