fixes:
- fixed the mess of options and general inconsistencies between program
man page and help message
- fixed some cases where rivet should fail but didn't and specified
return values for all exit conditions
- fixed the header system, before the header would have been added
inside of <head></head> which is incorrect, browsers would fix it
on the fly but still it is not correct.
Now _header.html contents are put inside <header></header> at the
beginning of <body>
- fixed <footer> outside of <body>
- some fixes in the man page
additions:
- added the requirement for _metadata.html, this file contains tags
and html metadata that is put inside <head>
- the main article is now enclosed inside <article></article> tags for
better styling
changes:
- rivet now generates an atom feed with the last 3 (configurable)
modified articles
- rivet now generates links in the index list to html files in srcdir
- Articles with unkown title will have their filename as the title
- minor code refractor
