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
Retabbing the whole document. Now using STY variable to detect if you're in screen and TMUX variable to detect if you're in tmux. Added SCresize function to be able to resize the sclang output split/ region (which in turn just calls the screen and tmux primitives for resizing). Added the possibility to change between vertical and horizontal splits. Set the width/height of the split to a safe default value (30 blocks/lines). Fixed the way scvim in screen closes itself (now effectively kills the other regions when closing/restarting scvim). This commit makes scvim work in screen and tmux equally
Retabbing whole document
Retabbing document. Adding presets for scvim run from within terminal multiplexers like tmux or screen.
Added explanation for SCresize function, added pidof as required dependency (it's used to kill spawned processes on closing scvim).
Classlib: PlotView: Don't post spec in calcSpecs
Merge pull request #1135 from jamshark70/topic/removeNeedlessPosts

Classlib: PlotView: Don't post spec in calcSpecs
help: fix typo in README
update tutorial
ide: dumpOSC is updated in GUI. Issue #1136 remains unfixed though.