[Fix #444] Add command prelude-update-packages
New keychord xx -> execute-extended-command
[Fix #447] Extract ido config into a module

This should make it simpler to disable ido completely if you want to use
an alternative library (like `icomplete` or `icicles` for instance).
[Fix #451] Add the ability to preload personal code
Fix typo in prelude-ido
Merge pull request #452 from jjcomer/master

Fix typo in prelude-ido
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)
Adding all my prelude customizations.
Renamed personal prelude files because I'm going to add a provide statement to the Elisps
Adding provide statements, plus figured out how to get smartparams to do strict mode (a la Paredit's undeletable parantheses
Add integration for OS X documentation app Dash
Optimize for Apple keyboard layout.
Add (hopefully behaving) support for Emacs Speaks Statistics.
Enabling strict smartparens mode on non-Lispy things has proved more trouble than it's worth.
Disabling ESS because I suspect doesn't play as nicely OOTB w/ Prelude as I'd like.