Add first cut at integrating S. Millers' system monitor.

At the moment it requires psutil to work.
Refs #9843
Add a check for the psutil package

The system monitor is only made available if this package is present.
Refs #9843
Fix order in which psutil check is applied.

The scripting environment needs to have been started before we can
check for the package.
Refs #9843
Install the SysMon utility to include it in the package

Refs #9843
Don't use negative sizes in the max width settings.

Refs #9843
Updating to SysMon v0.23

Refs #9843
Merge branch 'master' into feature/9843_integrate_sysmonitor_widget

Conflicts:
	Code/Mantid/MantidPlot/CMakeLists.txt
	Code/Mantid/MantidPlot/src/ApplicationWindow.h
	Code/Mantid/MantidPlot/src/Mantid/MantidDock.cpp
	Code/Mantid/MantidPlot/src/Mantid/MantidUI.h
Refs #9843
Fix bad merge conflict resolution

Refs #9843
Merge branch 'master' into feature/9843_integrate_sysmonitor_widget

Conflicts:
	Code/Mantid/MantidPlot/CMakeLists.txt
Refs #9843
Update SysMon to v0.26

Refs #9843
Merge branch 'feature/9843_integrate_sysmonitor_widget' into develop