Fixes to make BlockFunction::enumerate() compile in all cases

Commit
- makes EdgeDoFFunction::enumerate() public
- adds inclusion of FunctionProperties.hpp in BlockFunction.hpp
- performs a hotfix in DGFunction class, as there was an inconsistency
  between uint_t and ValueType (low level implementation in DGVertex,
  DGEdge and DGFace expects to receive uint_t, but was passed ValueType,
  which fails e.g. for double)