Don't unnecessarily reload the file type / syntax

During a debugging session I noticed that the notes file type was being
loaded multiple times for a single :edit command. This makes things
unnecessarily slow so it should be avoided. Done :-)
Make :NoteFromSelectedText compatible with selection=inclusive (issue #36)

Issue #36 on GitHub:

  NoteFromSelectedText trims the last character of a visual selection
  https://github.com/xolox/vim-notes/issues/36