slow tests and fast tests

[Tim Menzies]

for proj4, we need to define

(test-all-fast) ; for a set of tests that run in under 60 seconds

and

(test-all-slow) ; for tests that take a loooooong time

i will run (test-all-fast) in the reviews on the week of dec11.

but the 10*10-ways on 20 datasets times different row/column pruners
times different learners is a sloooooow test. the results of such slow
tests should be cached, summarized, and included in iccle.pdf (and, if
appropriate, analyzed using friedmann/nemenyi)

t