Ref #41 : Add resource declaration

Since widget are asking for those requirements, we need to declare them.
Ref #41:add resources to deform's default registry

To avoid breaking deform's resource handling mechanism, we need to
register deform_bootstrap requirements in the default registry.
Ref #41 : add some tests on resource registration
Merge pull request #44 from tonthon/bug_#41

Bug #41 : register resources to deform's resource registry