Use named functions with keybinding form

This allows DrRacket to display those names in listing of active key
bindings instead of just file name and line numbers, increasing
discoverability of added key bindings.
Add additional keybinding for other platforms

This modifies the define-shortcut macro to enable specifying multiple
shortcuts for commands, and then adds other versions of key bindings
that work on mac without command key specified to be working as meta.
Merge pull request #2 from pitkali/mac-compatible-keys

Mac compatible keys
add c:[, c:] for barfage
add auto reindent
small adjustment
simplify
Add esc; binding for paredit-down-sexp
Automatically generate esc; key bindings

So that nobody every again forgets about adding them.
Don't list esc; key bindings in README

Add a note instead, that all m: key bindings are accessible using Escape
like in Emacs, and explain where to see the actual list of applied key
bindings in DrRacket.
Add some comments for define-shortcut internals
Merge pull request #4 from pitkali/auto-esc

Automatically generate esc; key bindings