CallCandidateArg wrapping, logging, better hierarchy.

Added
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- Added println() function to stage::Stage to facilitate controlled emission of information.
- Split up updateHierarchy() into another updateHierarchyOfChildren() virtual method which is now overridden by subclasses. This allows easy updates to a node's hierarchy if new child nodes are added in a stage.
- FindCallCandidates now wraps the call arguments in a CallCandidateArg node. This allows easy generation of casts and the like later on.
FuncDef for binary and unary operators.

Added
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- func *operator* ... declares a binary operator
- func unary *operator* ... declares a unary operator