BUGFIX-66

Bug 14: Bad Code For A Bad-Byte Shift

This is a fast-in-practice string search, looking for needle in haystack.
It compares needle against a substring of haystack. If they match, the search is over.
Otherwise, it jumps forward in haystack by some number of bytes and compares needle again.
The jump distance is determined by the first byte following the compared substring in haystack.
If that first following byte does not occur in needle, the jump distance is len(needle)+1 bytes.
Otherwise, the jump aligns the first following byte with its last occurrence in needle.