v0.2 - dict, optional, abstract, children, infinity

new language features:

• nyan file format version numbers
• optional members - can be None or a value
• children object members - can only hold heirs of the speficied object
• abstract object members - can hold object where not all members have values
• dict members - key-value storage with arbitrary types (keys must be hashable)
• infinity handling for numbers
• int and float compatiblity