update
update
Merge pull request #11 from yixuanx/master

Pull
too many args to [] shouldn't throw an error

Discussion: http://arclanguage.org/item?id=17558
Uses a lesser-known feature of make-br-fn.arc: '__ is a rest arg.
  https://github.com/nex3/arc/commit/fb7427df7d
better name for lastcdr: lastcons
cleaner []
some unit tests
support improper lists in find
.
support improper lists in mem
support improper lists in 'some'
now pushnew works like push always did:

  (let x 3 (push 2 x)) => '(2 . 3)
simpler make-br-fn using all this improper-list support
roll back pull request #11 with site-specific stuff
eliminate some unnecessary uniqs
new test for pushnew: http://arclanguage.org/item?id=17582
.
two helpers for reloading files at the repl
helper: pipe text to an external command
separate functions for login and signup

We're going to be tweaking signup.