[#99] now pass the elapsed time information as a parameter to the `Renderable.update()` function

I added this after reading the newly added section in the wiki about the
melonJS core where Aaron was highlighting that this was currently
missing.

This will better ensure that we have a "stable" time information passed
to all objects, simplifies code and finally better leverage the new main
loop implementation using RaF, as anyway the information was there (just
not really propagated to objects)