Add support for <img/> tag for images (as an option).

Enable downloading stylesheets and input files when url specified
(later).

Consider renaming some command-line options.

Consider adding built-in stylesheets to the program.

Add support for <abbr> tag for most common used abbreviated forms (as
an option). Users should be able to specify them.

Consider adding (as an option) support for <hr/> tag. For example, if
line content is '---' or '-- ', the whole line will be replaced by
<hr/>. User shoulds be able to specify characteristic strings.

Fix issues with some chars.

Enable adding W3C "Valid XHTML!" button at the bottom of the
document, and, if user didn't specify his own styles, "Valid CSS!"
button.

Add recode library support.

Add support for configuration files.

Enable setting font size of document.