Feature request: o-table should support Multiple Filters

[rowanmanning]

@kitkat119 is building a filtered table for Junior Squad, for the IP catering app, and they'd like to be able to apply multiple filters to a table.

I'm not sure whether it makes sense to extend o-table filtering to support this, or have an example somewhere for multiple filters.

[notlee]

David Balfour is working on a Spark prototype which uses a text input as a filter. They would like to be able to use multiple filters, to filter using checkboxes also:

Update: Spark have implemented their own filters, so this isn't an urgent priority, but would be a useful feature to build for future users

[notlee]

Also requested by response.in.ft.com. See previous attempt to add this feature: https://github.com/Financial-Times/o-table/pull/253