Fix scope issue with "rss" variable

Instead of using `var rss = options.rss`, middleware now uses `var
config = options.rss`.
Implement better handling of pkg.author data
gitignore feed.xml
Remove grunt dep for reading package.json
Implement better fail function

Uses `process.kill()` to stop Grunt instead of `grunt.fail.fatal`.
Add space on line 12
Update failure message
Add documentation to message() func
Update docs
Implement support for "rss: false"
Attach fail function to description
Remove duplicate dep
Remove extra space from utils.js