This change reverts the RTree API back to the original one (i.e.
insert() instead of put(), search() instead of find()), and
creates a new searchReturningObject() method that returns an
object keyed by UIDs.
It also adds missing tests for type restricted search and
searchReturningObject().
Not using Math.max and Math.min increases performance, and by
using ol.extent functions instead of RTree's rectangle
structures and calculations we can get rid of several functions.
This new implementation is based on
http://github.com/imbcmdth/RTree/, with only a few modifications
to add the optional type and provide the API of the previous
implementation.
There is still room for optimization, but this is such an
improvement over the previous RTree already that it's worth
bringing it in now.
By doing the type check before the intersection check, we can
save he intersection check for cases where we don't care about
type or have the specified type in a node.
The RTree can easily maintain an additional index dimension,
by passing a type with each added item. Now instead of
maintaining an RTree for each geometry type, we have a single
RTree with a type filter. With this change, using the RTree
finally speeds up rendering as expected.
