fix generators/rand-range to handle/emit the full range of longs, fixes gh-37

Basic form pulled from data.generators/uniform, though that impl has
the same fundamental problem. Fixed by scaling the components of the
diff before actually determining the diff. This only works because
the random factor is a double, so the diff can exceed the range of longs
safely, but is brought back inside that range by the addition of
`lower` before being floored.
Update README with blog posts about simple-check
Merge pull request #42 from cemerick/master

fix generators/rand-range to handle/emit the full range of longs, fixes gh-37
Fix interpose test

The test was not actually testing anything, as we were comparing
equality with nothing, which always returns true.

Fixes #51
Put docstring in the correct place

Fixes #50
Fix typos

Fixes #49
Fixes #43
Fixes #44
Add Gagliardi blog post to README
syntax-quote default argument arity of defspec macro, fixes gh-48
tweak clojure-test tests to print output of each test run from the ns hook