Import ruby-electric.el 2.0.

* misc/ruby-electric.el: Import ruby-electric.el 2.0 from
  https://github.com/knu/ruby-electric.el which integrates changes
  from another fork by @qoobaa.
  * Allow ruby-electric-mode to be disabled by introducing a
    dedicated key map.  Electric key bindings are now defined in
    ruby-electric-mode-map instead of overwriting ruby-mode-map.
  * Add ruby-electric-mode-hook.
  * Use a remap in binding ruby-electric-delete-backward-char.
  * Totally revamp electric keywords and then introduce electric
    return.  Modifier keywords are now properly detected making
    use of ruby-mode's indentation level calculator, and
  * block-mid keywords (then, else, elsif, when, rescue and
    ensure) also become electric with automatic reindentation.
  * Add standarized comments for ELPA integration.
  * Fix interaction with smartparens-mode by disabling its end
    keyword completion, since ruby-electric has become more clever
    at it.
  * The custom variable `ruby-electric-keywords` is changed to
    `ruby-electric-keywords-alist`, allowing user to fine-grained
    configuration.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43251 b2dd03c8-39d4-4d8f-98ff-823fe69b080e