Added my personal version of ruby-build to rbenv. Life just got a little bit easier.
Put it in the wrong place.
Updated ignores with my tweaks.
Added a new plugin for rbenv.
Updated ruby-build information.
Merge branch 'develop'

* develop:
  Guard against exported `CDPATH` (fixes #316)
  Suppress shell warnings when hashing is disabled by `set +h`
  Add `rbenv --debug <command>` as a shortcut for setting RBENV_DEBUG=1
  Export PS4 when RBENV_DEBUG is set for more informative debug output
rbenv(): preserve multiline output of `sh-*` commands
Fix multiple argument completion with zsh

This changes the zsh completion to omit the final, incomplete command
line argument when invoking rbenv completions, making it consistent with
the bash completion.  Since no built-in completion cares about the
argument list, this inconsistency only affected plugins.
Merge remote-tracking branch 'sstephenson/master'

* sstephenson/master:
  Fix multiple argument completion with zsh
  rbenv(): preserve multiline output of `sh-*` commands