Introduces namespaces.

With namespaces in place, we drag the application into the future. The
namespaces adhere to psr-0.

This is the first step towards #5. The second (and probably last) step
will be to introduce the "use" keyword.
Removes misguided error code from GoodLooking

Handling errors is still a mess and needs to be fixed, but it's no longer
as misguided as it was (echo'ing html comments, js popups and messages).
Currently, it's aware of its shortcomings.
Fixes datetime primitive bug introduced in c0003fe

When using a datetime field, no value would be valid.

It was validating it against non-fully qualified name, so it was using a
class local to the namespace. This class did not exist so no value was
valid.
Introduces the use keyword.

Making the previously introduced usage of namespaces a bit more
userfriendly, the use keyword is introduced in a number of places.

This closes #5