Implement find symbol
Implement symbol renaming

Currently this doesn't work unless one first loads the buffer into the
repl, which is weird.  At least it wasn't obvious to me how cider was
involved.

The middlewere actually reads files, so any changes not saved to file
won't be reflect in the renaming.  We've taken it upon ourselves to at
least save the current buffer, but we might consider saving all project
buffers or prompting the user.

I've also not found a way to temporarily suspend the recording of undo
information.  I'd prefer we not litter the undo list and have the user
undo by just renaming again, rather than hitting `undo` x times where x
is the number of refactored occurrences.
Rely on cider for var-info when searching/renaming

I've updated the required cider version, from 0.6 to 0.8-cvs and added
it as a development dependency.  There was already a `(require 'cider)`
in clj-refactor.el so this won't really affect anything.

I've removed the branching on cider version, it was getting to be
annoying to maintain and it's not something I want to keep around
long-term while cider is below 1.0.

This commit also adds keybindings for find-symbol and rename-symbol and
corrects previous spelling mistakes (middlewere instead of midleware).
find symbol and rename symbol async

- calls refactor middleware async for both find and rename symbol
- find-symbol-buffer built async turned into grep buffer at end
- uses grep mode instead of compilation mode for find-symbol-buffer
follows up changes due to clojure-emacs/refactor-nrepl#8

... and fixes find 3rd party symbol from where it is used also fixes
broken remove debug fns
adds tests for rename symbol clojure-emacs/refacor-nrepl#6

- fixes couple of bugs
  - region to run replace-regexp against fixed
  - name to replace needs to get regexp quoted
rename find-symbol->find-usages
tweaks rename symbol

- nice msg when finished
- doing replaces in the background
- adds find usages and rename symbol to the readme
prompt for dir to search in for find usages

... and rename symbols

- defcustom to default to project dir without asking
fixes required refactor-nrepl version
Merge branch 'rename-symbol' and gets ready

... for release 1.0.0 wrt #78

- adds fu - find usages
- adds rs - rename symbol
- explicit dependency on cider 0.8.1
- explains dependency on cider and particulars about loading/evaling
  code because of AST building in refactor-nrepl

Conflicts:
	README.md
	clj-refactor.el