Re #6201. Moving from builtin NeXusCPP for to system installed library
Refs #6201. Fixing headers in tests.
Refs #6201. Fixing linking.
Re #6201. Changing to int64_t versions of methods.
Re #6201. Requiring NeXus v4.3.0.
Don't set the value for run_start until we actually receive...

...a run status packet.

Refs #6424
Use Poco::ScopedLock instead of explicit lock/unlock calls

Refs #6488
Use a mutex to protect access to run properties

The live listener has multiple threads that modify an event workspace.
It already uses a mutex to protect access to the workspace, but one
thread was modifying properties on that workspace without locking the
mutex.

Refs #6536
Re #6366 Fix EQSANS dark current for API v2
Select libNeXus.so in dlopen.py Refs #6201

This is required for some Linux systems.
Turn off precompiled headers. Refs #6486

Issues have been seen with them so they need to be looked at.
refs #6528. Make peaks re-shapable.
refs #6528. Allow presenters to reshape peaks.
refs #6528. Peak Preferences hooked-up.

Added components to all tiers to support this functionality. Have also extended the tests to cover the new functionality.
refs #6528. Fix no-return error.
refs #6528. Fix tests and warnings.
Re #6366 Fix hfir dark current subtraction
refs #6528. Upgrade following review.

Nick suggested a help link as well as images indicating what to expect at each end of the scales.
refs #6528. Correct includes.
Re #5366. Disable 'Add' option in combobox for histogram listeners.

And select 'Replace' by default instead. Marginally smarter way of doing
it than the previous way.