Enable Lexer and Parser object reuse, add 3D and 4D tokens

[djlambert]

• Parameter is no longed required on Lexer and Parser instantiation.
• Parser now creates a single Lexer and stores in a static var.
• Modified Parser::parse() to accept a new value in parameter.
• Tokens for 3D and 4D geometry added to Lexer.

[djlambert]

If there's no objection I'll merge this. I need fccbc0d for geo-obj.