Problem: Sourcing a script where a character has 0x80 as a second byte does
not work. (Filipe L B Correia)
Solution: Turn 0x80 into K_SPECIAL KS_SPECIAL KE_FILLER. (Christian
Brabandt, closes#728) Add a test case.
Problem: Using the system default encoding makes tests unpredictable.
Solution: Always use utf-8 or latin1 in the new style tests. Remove setting
encoding and scriptencoding where it is not needed.