Resolve "Main Constraint contravariance"

Closes #23

See merge request !12

Enables the no-fallback lookup for functions and constants

Fixes #22

Fixes #22

They're now included with the docker images

Make the message about the lock file being out of date go away.

Closes #19

It's been removed, so uses of it should error.

Updates test classes to extend the namespace version and changes
depreaction tests to test for removal

Everything is a namespace now, so make the tests fail.

Now requires HHVM 3.20.2 or later.