Only special strings starting with a dot are supported. Parsing of concatenated special strings using quotes needs to be implemented, but at least a few test-cases are already there now.
They don't define a KiCad string class, so the header file name was
somewhat misleading. But the fact that they didn't match definitely
made coding more difficult.
1) Fix a couple of bugs in case processing
2) Make case processing more explicit to prevent more (1)
3) Move label processing to AltiumSpecialStringsToKiCadVariables
4) Strip double-quotes from special strings (and add test cases)
5) Change PROJECTNAME to just filename, not full path
6) PROJECTREV and REVISION are two different things
7) Add support for Altium's Application_BuildNumber
8) Fix some issues in trimming spaces around special strings