Implement selection for Tet4 elements
new Part Primitives icons, display tree icons Part Line and Circle

New icons for Parametric Part Primitives
Point, Line, Circle, Ellipse, Helix

Display the icon in tree via independent viewproviders for
Part Parametric Line and Circle

Change Part Box tree icon to display yellow Part Box icon from the tool bar
add ViewProviders & Tree icons for Part Point, Ellipse, & Helix

Add ViewProviders to select an icon for the part primitives
Point, Ellipse, Helix,
Also return Part Box tree icon to "Tree_Part.svg"
Minor mod to icons for Part Circle, Ellipse,Helix, Line

reduce size of Circle, Ellipse,Helix, Line, within the icons
To increase their spacings so when stacked they don't collide
Add Tree icons for 3d Part primitives

This commit is just the icons themselves, not
the code to display them yet.
Tree_Part_Box, Tree_Part_Cone, Tree_Part_Cylinder,
Tree_Part_Sphere, Tree_Part_Ellipsoid,
Tree_Part_Torus,
Change the tree icon displayed for Part_Box

Change the icon file name in the viewprovider for Part_Box
Add Part Box, Cylinder, Cone, Sphere, Ellipsoid, Torus
tree icons to the Part.qrc file