Create bbox selection component

[ingenieroariel]

Users should be able to adjust their search query by either zooming in / out on the map or by refining the bbox within the map.

- [x] The bbox (q.geo) should be smaller than the map extent (a.hm.filter), so that users can see what's outside of the box - [x] The bbox (q.geo) should be able to be changed by dragging one of the six points (vertices or mid points) - [x] Area in the a.hm.filter outside of q.geo should have a washed out color to indicate to the user that it is not being part of the search results. (We can call this query padding) - [x] By default the value of that box (q.geo) should be [-90,-180 TO 90,180], the map should be zoomed out to show another copy of the world on each side. - [x] A heatmap should be displayed on the whole map (a.hm.filter). - [x] The heatmap should be updated after any update in the rest of the search form, the reset button from the form should take it back to the default.

Tags: OL3, AngularJS, High priority, Terrestris