[Fix #58] Add flycheck-compile

flycheck-compile runs a checker in a separate window under compilation
mode.  Intended for testing checker definitions.
Fix typo
Merge pull request #70 from ptrv/fix-readme-typo

Fix typo
Simplify Emacs Lisp checker

Just use `prin1-to-string` instead of a temporary bufffer.
Give checkers access to the original file name
[Fix #53] Add checker using checkdoc
Fix style issues
Copy-edit README
Show key combinations instead of M-x
[Fix #31] Chain checkers together

Allow to apply more than one checker to a single buffer.

See #32, and #53 for use cases.
Chain Checkdoc checker after Emacs Lisp checker [#53]
Add Emacs Lisp checker as example for chaining