[Util] Configurable brush alpha for PlotItem.
[Util] PlotItem now supports multiple points.
[CL] Store/access points history in proxy object.
[CL] BackendProxy::sumPoints().
[CL] Added tooltip item.
[CL] Show the tooltip item.
Merge branch 'cpuload'
[CL] Bigger history count.
[Util] Sane default alpha value for PlotItem.
[Util] Avoid frame in PlotItem by default.
[Util] Support plot titles in PlotItem.
[Util] Support custom backgrounds in PlotItem.
[Util] Added text color option to PlotItem.
[CL] Properly calculate item height.
[CL] Properly colored tooltip with header.