Fixed tag CSS in Jonah???

So, as you may have noticed, tag CSS doesn't really work in Jonah - past
passages don't retain their styles when advancing to future passages.
So, I've reworked the entire tag CSS mechanism for Jonah. Instead of
swapping #tagCSS's contents every passage change, it instead adds
[data-tags] selectors to the tagged stylesheets' code, and concatenates
them all into #tagCSS at startup.

The [data-tags] selector injection process is as follows. For each
selector in a style rule:
if selector has ".passage":
change to ".passage[data-tags~=tag]"
else if selector has "body":
change to "body[data-tags~=tag]"
else prepend "body[data-tags~=tag]"
This has the following effects, given what we know about the data-tags
attribute: rules for a .passage are kept for past passages, but rules
for, say, the page background, only exist when the tag is "in the
present" - when the present passage also has that tag.

This uses the CSS parser code from
http://code.google.com/p/google-caja/source/browse/trunk/src/com/google/caja/plugin/
under Apache License 2 (which I am told is MIT compatible).

This commit renders the "transition" tag non-functional for the moment.
An upcoming commit should reinstate it.
Four small tweaks, again

* Added position:relative to #passages.
* The Jonah toolbar no longer appears if Undoing is off, and the
"bookmark to here" link no longer appears if bookmarking is off.
* Custom scripts now have access to the interval used by
scrollWindowTo(), in the variable scrollWindowInterval.
* Copy-pasting passages in the story map now alters the pasted passage's
name to be unique.
Late bugfixes

* Re-added default transition CSS overriding in Jonah.
* Fixed the bookmark href being created too late in Sugarcane, producing
incorrect state serialisation.
* Fixed some implicit globals.
* Fixed Jonah's restart link not clearing the URL hash.
* Fixed pasted widgets' names having numbers appended unnecessarily.
Windows 1.4.0 release

* Output HTML files now print the Twine version in the license instead
of having a static version for each header.
* Fixed some version numbers.
OS X story format path tweak

* Jonah: fixed inline image syntax when used in tagged stylesheets.
* Fixed the OS X paths so that the targets folder is now inside the app bundle. Thanks @wolfteeth.
* However, story formats will also be sought in another 'targets' folder placed in the same directory as the app bundle. This allows other formats to be installed.