de-plaintext: Review Introduction
de-plaintext: Review Textformat chapter
de-plaintext: Marks during phone discussion
de-plaintext: Review Versioning Chapter
de-plaintext: Review Lilypond Chapter
de-plaintext: Review LaTeX Chapter
de-plaintext: Review Applications Chapter WIP
de-plaintext: Add new Frescobaldi screenshot

Reorganized the Frescobaldi screenshot to be better
recognizable in printout:
- increase code text font size
- detach the Quick Insert Tool
- use explicit \score block to be referenced in the text
plaintext: Remove obsolete draft file
de-plaintext: Finish review of LilyPond chapter
de-plaintext: Review LaTeX chapter
plaintext-de: Review applications chapter
Merge 'de-plaintext' revision