Add support for namespace at point.

Useful in snippets or for adding after license.
Make clojure-find-ns handle ns declarations with leading whitespace

- extend `clojure-namespace-name-regex` to allow zero or more
  whitespace characters before the ns form
Merge pull request #170 from phillord/ns-at-point

Add support for namespace at point.
Merge pull request #171 from ragnard/handle-space-before-namespace

Make clojure-find-ns handle ns declarations with leading whitespace
Correctly fill the docstring

First, use the fill-column setting of the edited file and not the global
one.

Second, fill the first line correctly. Previously the first line of
docstring could be filled to fill-column+1 characters, because the
initial " was dropped out of the fill calculations.
Merge pull request #172 from miikka/fill-docstring

Correctly fill the docstrings
Make the indent level of clojure docstrings configurable via
clojure-docstring-indent-level. Current default value is 2, but I would
argue most clojure projects indent to 3 (aligning subsequent lines with
the first letter of the docstring rather than the quote mark).
Set default docstring indent margin to 2 for backwards compatibility
Merge pull request #174 from AdamClements/master

Configurable docstring margin
Update the links in the front matter
Suppress compilation warning for paredit-space-for-delimiter-predicates
Improve a couple of docstrings
Update a few outdated links in the README
Toggle between string and keyword (fixes #173)
Bind clojure-toggle-keyword-string to C-:
Add clojure-toggle-keyword-string to the menu
Fix a bunch of checkdoc offences
Proper customization group definition
Unify customization prefix

According to major mode conventions it should be clojure- instead of clojure-mode-.
Remove obsolete abbrev table definition

We get it for free from define-derived-mode.