Intersection Type

[markwpearce]

Adds IntersectionType modelled after TypeScript's intersection types

• Add IntersectionType
• Add parsing for <type> and <type>
• Allow "Grouped types" in parser (eg: (type1 or type2) and (type3 or type4))
• Update type compatibility and other helpers to work with intersection types
• Verify scope validation
• Use order of operations on types, eg. type foo = myType1 or myType2 and myType3 or myType4 => myType1 or (myType2 and myType3) or myType4
• Make sure type MyKlassAA = MyKlass and roAssociativeArray works properly
• Add docs