Fixed the plurals header on `Catalog` which should only be written if it's not a catalog template. Added support to the frontends for `--msgid-bugs-address` that set's the `Report-Msgid-Bugs-To` header, which was also a missing header on `Catalog`, so, a bug found by chance :) (See #12, item 6)

[general]
input_encoding = utf-8
strip_comments = yes
toc_backlinks = none

[html4css1 writer]
embed_stylesheet = no
stylesheet = style/edgewall.css
xml_declaration = no