class compiler::ScanForUsingsAndTypes
sys::Obj compiler::CompilerSupport compiler::CompilerStep compiler::ScanForUsingsAndTypes
ScanForUsingsAndTypes is the first phase in a two pass parser. Here we scan thru the tokens to parse using declarations and type definitions so that we can fully define the namespace of types. The result of this step is to populate each CompilationUnit's using and types, and the PodDef.typeDefs map.