Facet Pivot, histogram widget, and pyramid widget

[cassisnaro]

This pull request contains the changes we have done to integrate the options of facet.pivot, and the two widgets we created. Sadly all our work is based on another database: one with comments published in meneame (a spanish website somewhat similar to reddit), so the data we used may not have any equivalent in the reuter's database.
In any case, the modifications we did in AbstractFacetWidget are all the ones related to pivots, and do not rely on which data is provided by solr.

[jpmckinney]

Hi @cassisnaro, can you add a commit to remove the files ending in ~? You can set up a global gitignore file to ignore files ending in ~. See https://help.github.com/articles/ignoring-files for instructions.

The PyramidAges widget looks too specific to your database to merge. I'm not sure if the histogram widget is too specific or not - do you have a screenshot of how it works? (GitHub can embed images).

[jpmckinney]

If you have a live URL where I can see the widget, that works, too.

[cassisnaro]

Sadly we all worked locally: we do not have a live URL.
In our solr collection we have comments, with the date of each one. If there is no filtering, or said in other words we have results for different days, the histogram shows 12 bars, each one for the amount of comments for a given month. The 12 months are consecutive, The first bar corresponds to the first month with results, so it may well happen that we are loosing information: we choose this option because we did not know how to deal with the overlapping labels.

Now, it may happen that the user select with the calendar some given day. In that case, the histogram detects that, and starts showing 24 bars, one for each hour. Of course this implies that the hour is stored in some field.

In the first scenerio, a fq is added with the given month as range, in the second scenario, the click adds a fq with comment_hour criterion.
I believe that I did what was required to erase the ~ files, so this should not be a problem anymore.