Permit syntactic symbols with CamelCase

[edubart]

Would be better if syntatic symbols also worked with CamelCase.

Motivation: I like to use CamelCase in my AST node tags because this permits to use reserved keywords in lua like Do Function Break etc in the code. For example I use a visitor pattern and declare visitor pattern to traverse my AST nodes like visitors.Do and visitors.Function, this is not possible with just lowercase then instead I've to use visitors["function"] = function(... due to the reserved keyword, but then I lose traceback readability from lua because I've to use an anonymous function.