Added a filter-comparator attribute.

[jantosi]

Now a different comparator can be specified for each row field.
This sets the comparator argument in AngularJS' filter.
If this attribute is omitted, the table defaults to a false value -- which means lowercase substring matching. If a function name is given, we will try to resolve it from the local scope and pass it as a comparator.

This is particularly useful when creating your own strict filtering on a field containing similar values (ie. "Field Unit" and "Field Unit Manager"). In the default behaviour, selecting "Field Unit" from a dropdown would match rows with both of the types.

This also allows for some degree of extensibility, allowing users to create their own comparators (think fuzzy-matching!).

[acd10]

Can you give an example of how this can be implemented?

[jantosi]

@acd10 This was some time ago, but having re-read this PR I believe this is how it works:

On each column definition, you can set filterComparator field to true, false, a function name or a function.

• true means strict matching is enabled for this field
• false goes back to default behaviour
• function (or a function name) specifies a comparator function when calling $filter('filter')(itemsFilteredWithComparators, currentPattern, comparator). Useful for custom logic.