Describe disabling key-chords in the README

It's good to have defaults, but nice to document a way of changing them
as well.
Merge pull request #324 from Abizern/key_chord_documentation

Describe disabling key-chords in the README
Remove problematic kk keychords
Override default move-beginning-of-line behavior
Add missing whitespace
Enable manually elisp-slime-nav (fixes #325)
Fix lisp code blocks in README.
Fix `prelude-smart-open-line-above`
Merge pull request #330 from seanfisk/fix-lisp-readme

Fix lisp code blocks in README.
Fix keychord mention
Merge pull request #331 from toctan/master

Fix `prelude-smart-open-line-above`
Add new command `prelude-top-join-line`

Saner version of the built-in `join-line`, that joins lines from the top
to the bottom.
Recompile the Prelude dir on `prelude-update`
Vanity URL for the installer

Made with
`https://github.com/bbatsov/prelude/raw/master/utils/installer.sh`

More info: https://github.com/bbatsov/prelude/raw/master/utils/installer.sh
Use valid shell commands

By not prepending `$` to your examples users can copy them easier
without fear of seeing `bash: $: command not found` or similar
Merge pull request #333 from joshuarh/vanity-url

Vanity URL for the installer
Merge pull request #334 from joshuarh/valid-shell-commands

Valid shell commands
Merge commit '82cc7188c2078eb739a52ad01efde7adcd099c59'