Add (unlock) more buttons (third line/row) to default TinyMCE editor::
- select font
- select font size
- select style
- text background color
- align justify
- underline
- new document (clear document)
- cut
- copy
- charset map
- horizontal break line
1.2.0: Verification has been added to see if, for example, another plug has added an option (then it is skipped).
1.1.1: Add "align justify" and "underline" (missed at WP 4.7)
1.0.1: First public ver.