Quickcheck

short answer: withdraw all r*-related tests.
test passed both on ccl 1.9 x86, SBCL 1.1.12.11-a566e33 .

Main change:
1: the amount of test cases are vastly increased.
Each test insert 200 (or 600) elements into the tree and run such test 200 times.
In each test every elements are created with a fresh random value.

2: added a test ':insert'.

Until the test passes with R*-tree, it should be noted as 'unstable' in the doc.