* tc-body transparent if background attachment
if you go fullscreen with the fullscreen button, the tc-body background color hides the background attachments - so make it transparent if $:/themes/tiddlywiki/vanilla/settings/backgroundimage isn't empty
* if background attachment macro
macro to make tc-body background transparent
In practice the macros are always invoked in inline mode, meaning that
the triple braces weren’t getting parsed correctly. Now we switch to
inline code
Move the CSS macros into global macros, and allow the colour macro to
fallback to the vanilla palette if the required colour isn’t found in
the current palette.
The new importvariables widget imports macro/variable definitions from
the specified tiddlers and makes them available to its children.
Allows us to split PageMacros up into separate tiddlers.
We still support loading macros from $:/core/ui/PageMacros to help
people upgrading.
Fixes#644 and #559
