Fix a few description typos
Correct 'is' to 'are' in koan description. 

I don't mean to be That Guy, but it's more correct to use 'are', rather than 'is' when discussing a plural subject. 
Merge pull request #36 from blt/patch-1

Correct 'is' to 'are' in koan description.
Touch up some grammar & wording
Bump to 0.4.7 for line number in message
Some slightly less confusing language for lein idiots like me
Merge pull request #38 from paytonrules/master

Some Minor Readme changes