Don't use real classes for faking entities.

Instead create a faked_class helper that can be used
in the project.
Move faked_class helper into spec/helper.rb
Use fake_class in all specs which used real consts
Don't use real Subject class in resolver_spec

* closes #12433
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Add spec and implementation for save_and_load
Add spec and implementation for save_and_load

Fixes last commit, broken by add --patch
Refactor Store::Repo spec
Remove typo.
Merge pull request #9 from janowiesniak/fix-specs

Fix specs
Fix typo in Store::Repo spec
Merge pull request #8 from janowiesniak/save-and-load-entities

Save and load entities
Bump version to 0.0.6