Merge pull request #3 from vietj/master

Minor API improvements + doc in README
Merge branch 'master' of github.com:vietj/codegen into vietj-master
Provide the package of the treated model as ifacePackage
Provide the package name in TypeInfo.Class
Use source elements only when it is present and fallback on the class based element instead
Type package renaming
Make kind available on all type info
Correctly handle kind for parameterized types
Handle case where a type variable is the argument of type argument
Keep track of the type declaring a method in the MethodInfo