Follow renaming of ReactEditorView to EditorView

Matches atom/atom@3d2d8c4 which is included in Atom 0.124.0.
Merge pull request #64 from AluisioASG/no-react-prefix

Fixes #63. Fix compatibility with Atom 0.124.0.
See #63, #64. Add backwards comptability for fix when used with newer Atom.
Prepare 0.12.1 release