Tests `property` `num-tests` times.
Takes optional keys `:seed` and `:max-size`. The seed parameter
can be used to re-run previous tests, as the seed used is returned
after a test is run. The max-size can be used to control the 'size'
of generated values. The size will start at 0, and grow up to
max-size, as the number of tests increases. Generators will use
the size parameter to bound their growth. This prevents, for example,
generating a five-thousand element vector on the very first test.

Examples:

    (def p (for-all [a gen/pos-int] (> (* a a) a)))
    (quick-check 100 p)