[API] Changing parameter order in graph_algorithms module.
[INTERNAL] Split up the graph_agorithms module's graph_algorithm.h header.
[NOP] Normalizing whitespace in graph_algorithms module.
[API] More graph cleanup.
[API,INTERNAL] Fix parameter order for graph and index property maps.

Also major cleanup of graph_property.h.
[API] Removing Raw Internal Maps for graphs.

Users can and should use the InternalMap<> wrapper for this.  The
generated code should be the same.  Anyway, I believe that nobody is
using this in the wild anyway.
[FEATURE] Cleaning up property maps.
[DOC] Improving property map API documentation.
[FIX] Changing parameter order in weaklyConnectedComponents().
Merge pull request #630 from holtgrewe/feature/graph-functions-parameter-order2

Feature/graph functions parameter order (v2)