Add prefix arg support prelude-update-packages

With a prefix arg it will update all installed packages.
Merge branch 'master' of github.com:bbatsov/prelude
Fix epl-upgrade invocation
[Fix #433] Disable problematic binding M-[
Simplify sexp wrapping code
Add wrapping commands to ielm-map
Improve tab's behavior

It now does both indentation and completion (when supported)
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  Improve tab's behavior
  Add wrapping commands to ielm-map
  Simplify sexp wrapping code
  [Fix #433] Disable problematic binding M-[
  Fix epl-upgrade invocation
  Add prefix arg support prelude-update-packages