Weld Servlet still uses old Google Collections instead of Guava

Even though WELD-564 is fixed, the latest version of Weld Servlet still includes the old Google Collections code. I think it should not contain the code at all and instead use a dependency on the library. Or at least update to the latest version of Guava.

The problem is that it makes it impossible to use Guava in the same classpath as Weld.