Move text and title extraction to separate functions
use get_html_file_content while building index and RSS
cut text (leave up to "<!-- text cut -->") in index and RSS

note that when requested to cut entry, it keeps stuff between text end and
entry end, so twitter button will still find its way into RSS feed

also fix indentation
"Read more..." link for articles which were cut
get_post_title in make_rss(), too
make cut_line confugurable
make cutting optional