renamed the testing system: spatial-trees-test -> spatial-trees.test

also, enabled testing of the NNS subsystem from the toplevel (= spatial-trees)
bugfix: load some structures at the compile time.
NNS on r* fails, on clozure cl! removed the test (activated only on sbcl).
Merge pull request #5 from guicho271828/clozure-cl-fix

Clozure cl fix