Fixed titlecase usage

I noticed that if the "titlecase" option is true then the post titles are converted to titlecase in some places and left unchanged in other places (archive, RSS feeds). First commit fixes this and uses for the value of "titlecase" option everywhere.
The second commit properly escapes the site title and post/page title in RSS feeds. They are properly escaped in the entry titles, several lines of code below, but not in the feed title.