A diff was already truncated after 200 lines. But it could still be
arbitrarily enormous, if a spammer or other random noise source likes long
lines. That could use a lot of memory to html encode etc the diff and fill
it into the template. Truncating after 100kb seems sufficient; it allows
for 200 lines of up to 512 characters each.
This works around a perl crasher bug, and also avoids bloating pages
with enormous diffs.
rcs_recentchanges modified to return a list in an array context.
* rcs_diff is a new function that rcs modules should implement.
* Implemented rcs_diff for git, svn, and tla (tla version untested).
Mercurial and monotone still todo.