Add support for tweening values relatively. #72

When creating a new Tween instance, all object proprieties is now stored
on '_valuesStart' instance variable, for possible further increment, by
the relative tweening behaviour.

When using 'repeat' method, the start value will be updated at the end
of each animation.

There is a usage example on '09_relative_destination.html'.
Add tests for tweening values relatively. #72

Don't prevent interpolation of null values or of non-existing
properties. They should now always start as zero.
example 08_repeat: remove commented code
Remove 'Floweroscope' from list of featured projects as the domain has expired and the site is not available any more
Add comment about not checking in tween.min.js
Merge branch 'dev-relative-destination' of git://github.com/endel/tween.js into dev
Make example 9 more JSHint-friendly O:-), also fix title to be 'relative destination', and use minified tween version
Pump revision up to 10dev. Also fix various style thingies here and there.
rename example name: from relative destination to relative values
add more data about example 09 and relative values feat
err... proper example filename
revision -> 10
fill in missing release information