Restricted plugin namespaces

[skellock]

Prevent these namespaces from being defined in 3rd party plugins:

• spork
• project
• gluegun
• default

If we see those namespaces, we should just go into a badnamespace error state on the plugin.

[skellock]

After a good sleep:

spork - This is the first core-plugin. Something isn't quite sitting right with me here. I can't put my finger on it.

project - Yup, no problem. The project namespace represents access to the project-based plugin in the ./gluegun directory.

gluegun - I'm not sure why I added this to the list. spork is it's own namespace.

default - I'm not sure why I added this either.

So, for sure, let's add project, but jury is out on the other ones.

spork would cause a collision if someone made a plugin called spork. Or if someone made a command called spork in branded mode. But if we have a collision disambiguation feature, this wouldn't be an issue.

So let's make project reserved, and revisit the others later.

[skellock]

#64