Don't show busted stack frames in tracebacks.
Don't show busted stack frames in tracebacks.

This patch filters out any stack frames from within busted itself from
tracebacks printed via 'busted -v'. It looks for the deepest stack frame
that is inside the test file, and discards everything after that. If no
stack frame exists within the test file then the error is within busted,
so the entire stack is shown.

xyliuke/busted,istr/busted,sobrinho/busted,ryanplusplus/busted,mpeterv/busted,o-lim/busted,leafo/busted,DorianGray/busted,Olivine-Labs/busted,nehz/busted