Added base exception.
Merge branch 'master' into exceptions

* master:
  Rephrased comment.
  Added Kasper to credits.
  Removed markdown rendering.
  Rewrote how the cli works to inject dependencies.
  Reduced some duplication.
  Added cli plugin loading.
  Removed ext folder.
  Added ext folder for plugins.
  Restructured cli a little.
  Added list of plugins to config.
Merge branch 'master' into exceptions

* master:
  Fix minor typos in the README
  Mention beetle-example project in README file
  PEP8 and Pylint clean up
  Added a 'help' command which display the available commands
  Provide an empty list as default value for plugins
  Refactor typo away: renderes -> renderers

Conflicts:
	beetle/builder.py
Added renderer exceptions.
Added NoUrlError.
Renamed error.
Allow the BeetleError class to take a page object as an argument
Add the page which gives the error to the exceptions
Include the file system path in page object

This makes it easier to give some useful error messages to the user in case of an error
Merge pull request #12 from Tenzer/exceptions

Add meta data to exceptions
Cleaned up url making a little.
Added filename to page dict.
Added messages to exceptions.
Removed filename because path was already there.

I just didn't see it at first.
Removed comment.
Better pep8 too.
Reworked BeetleError to have less hackery.
Upped version number.
Fixed msg problem.
Merge pull request #11 from cknv/exceptions

Exceptions