Suppress byte-compilation warning

This takes care of the byte-compilation warning
about a reference to a free variable `paredit-version`.
Fix a couple of docstrings and indentation errors.
Use should instead of assert in tests.
Docstring additions and fixes.
Simplify popup buffer quit/restore using `quit-window'.
Update copyright year and add link to contributors.
Fix #199 - make *nrepl-src* closable with 'q'

`nrepl-popup-buffer-mode` was misbehaving originally, but the recent
refactoring of the popup window quit/restore logic fixed the problem
and now it's ok to use `nrepl-popup-buffer-mode` together with
`*nrepl-src*`.
added a basic check for an existing REPL buffer in nrepl-jack-in & nrepl
Use nrepl-symbol-at-point instead of eldoc-current-symbol for eldoc.
release v0.1.6
bump version
Merge pull request #162.  pprint mode for REPL.
Refactor REPL pretty printing code

The original version of the code had a few problems:

* use of defvar instead of defcustom
* wrong menu entry for the toggle command
* missing docstrings
* fairly obscure names
Merge #241 - Refactor nrepl pretty printing.