first draft.

seems to be quite flexible.
Things to try: calculation of the new srcInfo should not be a fold using (srcInfo -> srcInfo -> srcInfo), but a function that sees more, e.g. [(srcInfo,param)]
renamed and generalized a few things
slight generalisation.
no idea what I did. compiling
compiling. experimental only
the complexity cannot be solved generally.

specific things cannot be solved generally, but are part of a specific use case.
There seems to be no way how renderMethod combinators like "horizontal" or "vertical" can have the same renderparameters or srcInfo like "renderToBlock".
This means: there seems to be now way how horizontal and vertical can be chained, in a general way.
Therefore I tried this:
	to combine renderFunctions, one has to define many things manually. Therefore the combinators "horizontal" and "vertical" take some more (function) parameters.
added a combinator for tuples of sources
deleted some some old commented code
new function renderTree. Not working yet, but compiling.

stumbled over a problem: the list combinators for RenderMethods don't work if the list is empty.
solved the problem when rendering empty lists.

in case the list is empty, a fill function is used ( :: renderParam -> repr ). This fillFunction is used just in case the list of sources is empty!
fixed SGRender.Block. Broke because SGRender.Render changed.

rendering a tree seems to work now!
cleaning everything up
now dependent on sgData-1.0, sgCard-1.0. Did some experimental changes as well.
great progress. Made an implementation of combinators for 2D blocks. Seems to work.

the difficulty was to decide, how concrete to code on every level.
There are several kinds of combinators, which are different in flexibility and generality.
These things are still to be documented.
nicify all. Added some doc. Some renaming.