Added comments to a bunch of functions (see below)

getScaled()
scale()
distance()
getInterpolated()
interpolate()
getMiddle()
middle()
average()
getNormalized()
normalize()
getLimited()
limit()
length()
dot()
Merge pull request #10 from creativethumbs/master

Added comments to a bunch of functions in of4Vec
Merge branch 'master' of github.com:CreativeInquiry/openFrameworks into feature-documentation