Simplify file/line blaming w/o tracebacks
Simplify file/line blaming w/o tracebacks

Also clean up error augmentation process code a little bit; e.g. add a
separate helper for adding file/line similarly to what is used for
tracebacks.

harold-b/duktape,tassmjau/duktape,harold-b/duktape,markand/duktape,markand/duktape,tassmjau/duktape,svaarala/duktape,jmptrader/duktape,jmptrader/duktape,harold-b/duktape,jmptrader/duktape,tassmjau/duktape,harold-b/duktape,svaarala/duktape,markand/duktape,tassmjau/duktape,tassmjau/duktape,jmptrader/duktape,markand/duktape,svaarala/duktape,tassmjau/duktape,harold-b/duktape,markand/duktape,harold-b/duktape,svaarala/duktape,jmptrader/duktape,markand/duktape,harold-b/duktape,svaarala/duktape,tassmjau/duktape,harold-b/duktape,tassmjau/duktape,markand/duktape,jmptrader/duktape,jmptrader/duktape,markand/duktape,svaarala/duktape,tassmjau/duktape,markand/duktape,harold-b/duktape,svaarala/duktape,svaarala/duktape,harold-b/duktape,svaarala/duktape,tassmjau/duktape,jmptrader/duktape,markand/duktape,jmptrader/duktape,jmptrader/duktape