Basic implementation of absolute positioning with top/left

* the manual crashes for me throwing some strange JRuby error
  when I change absuoletely_positioned? to always return false
  (why would I do that? well right now it's buggy kind of)
  Could not initialize class org.jruby.util.unsafe.UnsafeFactory
  don't really know what to do about that/how to fix it
* semantics are not exactly the same as the shoes3 semantics as
  those seemed inconsistent and buggy to me (e.g. when top
  is specified for an element in a flow it does not take that
  element into account when positionining next elements, but
  for left it does although that element is totally not at that
  place, left for stack did not seem to work etc.)
* some work to do to see if elements are absolutelty positioned
Information about whether or not an element was absolutely positioned.

* note this also includes the feature that DimensionsDelegations
  now automatically delegates to all public instance methods of
  the Dimensions class
* Omfg manual works again =D