Position tokens not supported by cpp-nostl backend

[andreasabel]

Position tokens lack support in the following backends, the test #235 fails now for these backends (since I added a position token declaration to the test case).

• Agda: AST binding ignores position component
• CPP-NoSTL: position has always been ignored, but fixes of Interaction between coercions and arrays causes syntax error. #100 (e8abd9f) and C++ backend: Skeleton files broken with user-defined tokens #277 ( 4fb4116) broke even generation of Printer/Skeleton
• CPP with namespace
• Java with jflex (this was actually JFlex special characters not escaped #299)

Remaining TODO (low-prio):

• respect position in token declarations in CPP-NoSTL backend.