Colour-related IDE improvements

* Now, special passages (Start, StoryAuthor, stylesheets, etc.) have
different-coloured title bars. I've tried to stick with earthy hues in
keeping with the colour scheme of the Twine icon, with redder hues used
for stylesheet and script passages.
* Now, connection lines representing <<display>> macros are drawn with a
bluer tint.
* Fixed the bug where importing .twee source code would discard all the
passage tags.
* Changed the unsaved changes dialog to give you the option of saving,
there and then.
* Fixed a small regex bug in the templates.
*
* Fixed the bug where importing .twee source code would discard all the
passage tags.
* Changed the '
* Fixed a small regex bug in the templates.