fix(environment): unglobalize environment after tests

The environment wasn't unglobalized after the run, and the
unglobalizeMember method was relying on a k argument where key was passed.
The runningSpecs also unglobalize the virtual environment to prevent
the old environment to cache the previously globalized methods.
feat($core): snakify matchers and matchers methods
feat(mixins): add set method on GlobalizableObject

The set method allow to add a property on the object that will be added
on global if the object was globalized.
feat($tests): helpers are now created with spectacular.helper

It allow to unglobalize the helpers at the end of the run by adding
the helper on a Globalizable object.
feat(matchers): provides rspec style matcher definition

The spectacular.matcher creates a new matcher with the provided match
function, optionally the matcher can be parameterized by calling the
takes method.
feat(mixins): support original method in snake case in Globalizable

Now, if a globalizable property is in snake case, the camel case
alternative will be also added to the global object.
docs(pages): update documentation with the latest changes

Includes:
  - new matchers definition syntax
  - helpers definition
  - snake case syntax