Implement quoted format string "$(a + b =)" => "a + b = 5".
-2.0 is now a float literal instead of an expression.
1f is equivalent to 1.0f.
Add Vulkan demo. Some C importer fixes.
--unittest now only enables unittest for the root package.
--unittest=name enables unittests for the name package in particular.
Also some caching fixes involving case().