blog_clean() bug fixes.

Fixed a bug that caused the function to try to delete
.bucket3/_data/* instead of .bucket3/data/*.

Function also deletes .bucket3/fsdb/* now.
"render" runs bucket3.render_html_skel() now.
bug fix: archive entries sorted by date *desc*.
Preparing for v0.9.5. Added docopt dependancy.
Almost complete rewrite. Uses docopt.

This is an almost complete rewrite of bin/bucket3 to use docopt.
Code is more readable now, new (more comprehensive) options.