CCAction Improvements

[Birkemose]

I suggest introducing a more flexible action class, which is based more on tweening, than on running specific properties.
The class should amongst other things include

A progress method for normalized progress, which can be overriden for excactely the transfer function the user wants. As it is now, the user is stuck with an ease function, where he needs to dig deep, if wants to change it.

A transfer method, which can be overridden for excactely the output, the user wants. As it is now, output is only lerped, based on progress.

[slembcke]

Going to bump this up to 4.x. @andykorth looked into the transfer function issues. There are the CCActionEase classes, but my experience was that they didn't work. Andy found that they rarely worked, and that some of them simply used incorrect equations. We should really do something about this for 4.0. At least remove the broken functionality.