cleaning up trailing whitespace
emacs code cleanup
emacs: adding missing keyboardQuit command
add platform attribute to emacs handler to allow platform-specific keybindings

usage like:
editor.getKeyboardHandler().addCommand({
    name: "...",
    bindKey: {win: "...", mac: "..."},
    exec: function(e) { ... }
});
adding command key to emacs keyhandler.

usage:
keyHandler.bindKey("CMD-g": "someNewCommand")
comments for emacs handleKeyboard
adding tests for emacs handler
Merge pull request #1262 from LivelyKernel/emacs-improvements

Emacs improvements