It is quite useful sometimes to see that someone else (not you) has pushed
commit to remote. This change adds "C committed on D" phrase right after
"A authored on B" if author and committer are not the same person (judging
from email address).
With each new hunk, starting new line number was the same as starting old
line number. Parse diff line a bit further to get real new line number.
Fix HREFs for old line number links in both bootstrap3 and default themes
so that thay work.