Serialize package states independently of RootView
Serialize package states independently of RootView

Previously, package specs needed to deactivate the root view to test
their package serialization. Now, specs can just deactivate and then
reactivate the package, relying on serialization infrastructure that's
independent of the lifecycle of the RootView.

danielgtaylor/atom-api-blueprint-preview,grimmer0125/markdown-preview-kramdown,sctlee/markdown-preview,Galadirith/markdown-preview,tkssharma/markdown-preview,ArnaudRinquin/markdown-preview,atom/markdown-preview,makyo/markdown-preview,rugk/markdown-preview