Extract category_link filter from category_generator.rb plugin

Allows category_link to be used as a filter to display a link to
any category.
Added robots.txt, with sitemap link
init blog
post first blog
update code block lang
delete emacs generated mardown files
a blog about setup ocopress
update blog
update blog
ready for post
fix links
add about me page"
To support url without domain name like /path/file

You need to know if you would like to support this, each word in the title can not start with "/".
Fixing English error pet-peeve.
Merge pull request #831 from parkr/english

Fixing English error pet-peeve.
Rakefile option for any additional rsync arguments

Added variable `rsync_args`
gist tag plugin now works with the latest changes GitHub gists and does not fail if you do not specify a filename.
Merge pull request #824 from liangsun/patch-1

To support url without domain name like /path/file
Merge pull request #844 from jsvensson/rsyncargs

Rakefile option for any additional rsync arguments
Titles in code plugins can have slashes in them. Closes #892