rename Client -> ClientResource

prepare project structure for resource relocation
rename Cookbook -> CookbookResource
rename DataBag -> DataBagResource
rename Environment -> EnvironmentResource
rename Node -> NodeResource
rename Role -> RoleResource
rename Sandbox -> SandboxResource

add pending test for SandboxResource... I was bad...
rename DataBagItem -> DataBagItemResource
rename EncryptedDataBagItem -> EncryptedDataBagItemResource
Merge pull request #46 from reset/resources-rename

rename resource classes