This bugfix implements correct way to calculate source sha1 hash, before it will changed,
by propagation of unchanged sources.
This commit will also include regenerated static files and *.hash files.
This will make future diffs easier to read because code changes modify the
hash/link, but the image data stays the same.
Note that there are whitespace diffs in the generated files where there
is no image. This is because there was a stray tab in the template before,
and now it's replaced by spaces.
Fixes#235
