Separate LabelStatisticsFilter instantiation

Create separate instantiation files for 3D and 2D to register the
execute method in the factory.

Change-Id: I743d691fb7b698341f7bd27fa942cdea97c19c1b
Move manually wrapped from basic filters library 0

The Cast and Statistics files take a while to compile. By moving to
the later libraries there are less dependencies and thereby improved
parallel compilation performance.

Change-Id: Ib703b96136aa2117ea7e224c8374e9a6ac5b9b4d
Merge topic 'SIMPLEITK-450_BreakUpLabelStatistics' into next

b2c1dd3 Move manually wrapped from basic filters library 0
01f4d3e Separate LabelStatisticsFilter instantiation