Add code mirror.
Make the editor CodeMirror base.
Merge branch 'feature/code_mirror' into develop
Fix the bug where Tab character is inserted when pressing the tab key.
Synchronizes scrolles of the editer and the preview.
Adds resize method to NoteEditorView
Adds paraiso-light theme.
Replace the editor with the textarea editor.
Use the code mirror based editor.
Improve the behavior while entering Japanese text.