TODO list:
 	* rad auto-conversion, infinite symbol improvements

 	* init functions 

	* create a libspar.spec.in file

	* depht test the parser (create a test dir. with many tests!)

	* various writer impovements, such as:
		write math consts and symbols
		write angles (PI/2, PI, ...)
		write formatted math expressions 
		write tables 

	* configure.in improvements, such as:
		check the previous spar installation
		define the package and the version number
		freeBSD support
	
	* verbose message in the installation

	* create a complete API reference with doxygen
