fix. array types were not accepted as a generics type parameter.

Hi,

Thank you for the great parser library.

I've found a java7/Java7.g4 not accepting array types as a type parameter 
(in code such as the following), so slightly modified a definition of "typeArgument".

-----
        import java.util.List;

        class A
        {
                List<String[]> s;
                private class B implements List<String[]>
                {
                        int col;
                }
        }
-----

I'm not so familiar with the Java's grammar and have not checked this modification has
some unwanted side effects or not, however, this modification reduces parse errors when I run Java7.g4 at my side.

Regards,

- Toshihiro