Clean up exception definition

Use http://dustinsenos.com/articles/customErrorsInNode to improve
exception definitions.
Small, incomplete refactoring for plugin search
More code refactoring
Update TODO
Fix some silly errors
Fix test name
Beginning of a test
Merge branch 'master' into multihydra

Conflicts:
	lib/robohydra.js
Merge fixes
Rename exception to be more generic

DuplicateRoboHydraPluginException is now
InvalidRoboHydraConfigurationException.
Fix test

Use the new, more appropriate exception when checking for authentication functions
Use "summoner" and "robohydraPicker" as names
Check if the RoboHydra picker function is really a function
Give RoboHydras a name
A bit of refactoring
Fix some bug in fixture generator