Having underlined blue text everywhere was too noisy. This changes
the CSS style for internal links to be plain black text that gets
blue and underliney when you hover the mouse over it.
Also, added the current date and time to the set of template
substitutions.
If you play games with code hints you can create a data operand that
overlaps with code. This causes problems (see issue #45). We now
check for that situation and ignore overlapping data descriptors.
Added a regression test to 2011-hinting.
