`.editor` -> atom-text-editor

Ref atom/atom#4058
Prepare 0.43.0 release
Use TextEditor::onDidDestroy
Use new status event methods on GitRepository
Don't use path var name
Use decoration for icon class
Add icon class to .gutter element
Query root element
setPath -> setPaths
getRepo -> getRepositories
setPath -> setPaths
Use atom.views.getView for editor view
Use editor instead of buffer
getActiveEditor -> getActiveTextEditor
lineForBufferRow -> lineTextForBufferRow
Drop Cursor from methods names
Don't use atom.workspaceView
Use atom-space-pen-views
Add back path change subscription
Always use empty array instead of null