Fancier error messages for the parser.
Fancier error messages for the parser.

The error messages of the parser now contain surrounding lines of code instead
of only the offending line of code. This should make debugging a bit easier.
Line numbers are also shown for each line.

ttasanen/oga,ttasanen/oga,dfockler/oga,YorickPeterse/oga,ttasanen/oga,jeffreybaird/oga,YorickPeterse/oga,jeffreybaird/oga,YorickPeterse/oga,ttasanen/oga,jeffreybaird/oga,altmetric/oga,altmetric/oga,altmetric/oga,YorickPeterse/oga,dfockler/oga,dfockler/oga,dfockler/oga,jeffreybaird/oga,altmetric/oga,YorickPeterse/oga,altmetric/oga,ttasanen/oga,jeffreybaird/oga,dfockler/oga