parameter() and tags() changes

* Fixed annotation passages being drawn too dark in smooth drawing mode.
* Removed the thrown error from parameter() altogether, on the newly
considered basis that it would make variadic widgets difficult.
* Fixed a bug in a previous commit concerning
Wikifier.prototype.fullArgs().
* tags() can now take passage name parameters, much like visited() does.
Fixed obfuscation interfering with backslashes

* Fixed a bug where backslashes would be incorrectly converted to
arbitrary letters if passage obfuscation was being used.
* Added 'header' and 'footer' elements to Jonah's .passage elements, to
provide a bit more symmetry with Sugarcane's DOM layout.
Fixed <<back>> in specific situations

* <<back>> now works better when Undo is off in Sugarcane. Previously it
would mess up the variable state in cases when link variables were in
use.
* <<back>> and <<return>> now work when restoring a Jonah state via
bookmark.
* <<back>> also now works when clicked in a past passage - previously it
would act as if it was in the present passage.
* Fixed the IDE's monospace font using the normal font's size instead of
its own.
Fixed Jonah scrolling in IE 8

Previously it would scroll from the top of the page regardless of scroll
position.
Fixed a:link and visited(), added .visitedLink

* The CSS selector ":link" in stylesheets is now converted to
[class*=Link] at runtime. This is to provide backwards-compatibility for
people who used "a:link" to refer to Twine links (which is no longer
usable as internal links no longer have href attributes). It's a mean
sight of a hack, but so be it - I shan't be adding back the
"javascript:void(0)" href no matter what you say.
* Added the "visitedLink" class, which is applied to passage links that
link to already visited passages. ":visited" is converted to
".visitedLink" much like the above. This provides a surprising deal of
power - you can give .visitedLink "display:none", for instance.
* The StorySettings passage is no longer converted to all-lowercase at
build time. This should make HTML exporting/importing more symmetrical.