hgview #6857 bug displaying diffs *and* moved files [open]

a bug in hgview_gtk:prepare_diff represent all files as either a rename or a diff.

this is obvious looking at if diffmsg:... else:....

You need to parse diff headers for file names (l.startswith("diff")) and look if there is a corresponding message in diffheaders to choose between representing the diff as a rename or a real diff.

done in<not specified>
load left1.000
closed by<not specified>