Allow the Terms panel to ignore it's own filters

This commit implements what was discussed in #1126. It is also dependant on that pull-request for allowing toggling of filters (included here).

The change adds 3 settings to the terms panel config: "Filter mode", "Ignore own", and "Radio select".

It is useful for using the terms panel as a type of "selector" to easily flip between different term factors. The idea being that with this setting turned on, the terms panel will not be affected by the facet filters it added itself to the filtering panel.

Imagine I have a terms panel showing "Top 5 Pages". At the moment, if you click on one, you'll be left with only that single page name listed in the panel after it refreshes. With the 'ignore own' toggle all 5 pages will remain and can be clicked for toggling additional term filters.

I've also added some color overrides to the rendering to grey out any terms which are not being selected (if you select at least one term). The "Radio Select" mode allows that only one term filter can be selected at a time. If you have term1 filtered on, and you select term2, then term1's filter will be removed.

Lastly, the "Filter mode" setting allows you to specify the facet filters which are added to be 'must' or 'either' mode.

![](https://cloud.githubusercontent.com/assets/5456080/2872231/7b7a92dc-d350-11e3-8c2e-cac32d0b1eea.png)