Post-1.4.0 release bugfixes

* Moved the 'Test Play From Here' entry to the top of the passage
right-click menu.
* Fixed external link syntax highlighting.
* Added "vertical-align:bottom" to images to compensate for a
line-height difference in XHTML Transitional and HTML5.
* Fixed the <<nobr>> macro not working if any text follows it.
Unicode fix for build resources

This might ameliorate complaints that non-ASCII characters in build
resources (headers, the StoryIncludes files) cause builds to fail.
Fixed <<choice>>

I unwittingly made the "choice clicked" variable be unique to the links,
not unique to the passages. What should happen is that clicking a
<<choice>> disables all .choice links in the passage, not just itself.
Some variable-related fixes

* Fixed variables used as array indexes not being parsed correctly.
* Fixed syntax highlighting for shorthand <<print>> macros.
* Restored the left positioning of the Sugarcane sidebar.
Minor external link fix

* Added support for "javascript:" URIs in external links, and fixed
"mailto:" syntax highlighting.
* Also fixed it so that 'state' is undefined while script passages are
executed. This should fix a bug with some popular old scripts.
Updated the test play/start at passage feature to not force a variable on headers and to be header agnostic.