Issue #3 solved. Added grammar rules. Expecting Warning arg in cup.

- implemented unqualifiedId, opaqueEnumDecl, usingDecl, usingDirective,
namespaceAliasDef, among other xxxOpt rules.
- finished implementing blockDeclaration
- added expected warning of 10000 warning in cup.args (build
properties)
- added java-cup/runtime to solve issue #3