better name for lib/experimental.js
seriously, screw the lib directory

I've gone back and forth on this one; but for *now*, my opinion
is that this was a mistake, having all these separate files. I
kept modifying lazy.js directly and then calling `rake compile:lib` and
losing my changes. Or, I would modify the "correct" file, but then
forget to run `rake compile:lib`, and then be confused as to why my
change wasn't taking effect. Just a total mess. So I'm going back to
just sticking with lazy.js as a single file.
...which means I don't need compile:lib anymore
created separate filter_spec.js file
moved reject specs into filter_spec.js
created standalone reverse_spec.js file
concat_spec.js
take_spec.js
drop_spec.js