#51 Large files with little markup

[Tony Dodd]

A file with only one start tag and one end tag that
exceeds 1M in size will index content a few bytes
away from where it should be.

This is a bug in the Xerces locator - Xerces normally
reports content in a single event but clearly at
around 1M a buffer overflows and a division is
inserted, the reported location being exactly a line
out.

Needs a workaround but I can't immediately think of
one.