Refactoring

[benjchristensen]

• convert to rx.* package names
  • rx.observables
  • rx.observables.operations (private package from javadocs)
  • rx.util
  • rx.lang
  • rx.concurrency (placeholder for schedulers)
• change Func order to have return type at end => T, R instead of R, T
  • this matches the C# and Guava conventions
• added Action as Func without return value
  • added overload subscribe methods with Action typed arguments
• added from() alias methods in Observable