lang: include missing header
Classlib: GUI: Reinstate proper functioning of ObjectGui system

Patched by James Harkins <jamshark70@dewdrop-world.net>

Object:gui *should* look up the implementing class by the method
'guiClass'. Commit 019586cb0ba20d7c9d851e2449dac7911bbb0952 improperly
removed this and hardcoded ObjectGui instead -- thus breaking every
class that implements 'guiClass' but not 'gui'.

The crucial GUIs are not Qt views. They are more like Controllers
in MVC. 'guiClass' here was never a redirect and it shouldn't have
been touched.
class library: patterns: make cleanup optional in EmbedOnce stream
class library: patterns: Nil:update is already defined, so we can omit the test
Merge pull request #1072 from timblechmann/fixes/fix

lang: include missing header
class library: count only named controls for the limit number of controls
help: improve Pproto help by explaining a bit more and changing the order of examples
help: improve event type help
help: fix typo
cmake: disable some msvc warnings

Signed-off-by: Tim Blechmann <tim@klingt.org>
Classlib: Event: Make \monoNote convert symbolic addActions

This makes it behave like other node-creation event types.
Merge pull request #1074 from timblechmann/topic/silence_warnings

cmake: disable some msvc warnings
Classlib: Server.sc: Prevent an inadvertent "non-inlined function" warning
Classlib: SystemSynthDefs: Remove postln that shouldn't have been committed
Merge pull request #1076 from jamshark70/topic/unnecessaryPostln

Classlib: SystemSynthDefs: Remove postln that shouldn't have been committed
Merge pull request #1075 from jamshark70/topic/inlineWarnings

Classlib: Server.sc: Prevent an inadvertent "non-inlined function" warning
Merge pull request #1073 from marierm/fix-ObjectGui-system

Classlib: GUI: Reinstate proper functioning of ObjectGui system
help: improve SplayAz helpfile
class library: gui: refactor plotter setValue and simplify plot methods. This fixes #1077
help: add tutorial category to tutorials and update some helpfiles. This fixes #693