Update GUI-Layout-Management.schelp

I added example about the question why a UserView might not show up in a Layout.
Make use of tmux instead of screen. Includes splitscreen for SC output on the side.
Fixed SClangRestart and SClangKill to work properly (also without using from within tmux)
Disable AppNap in QtCollider, sclang, and scsynth
Add files I forgot to add in the initial commit.
Remove debug printf()s.
netbsd: use compile-time OS flag, in same places as freebsd - thanks Thomas Klausner
netbsd: Add missing header for strerror() - thanks Thomas Klausner
lang: use proper interface to get position within File - thanks Thomas Klausner
netbsd: avoid referring to QGtkStyle, not a public symbol - thanks Thomas Klausner
build rules: neater check for Linux-or-*BSD, thanks Tim Blechmann
Major cmake changes to get qt5.2 building
Tracking the qt method rename.
User QStandardPaths instead.
Explicit toString() required.
Tracking method rename.
Plastique no longer exists
Change order to get moc's
Include macextras
Remaining source changes to get to compile.