Memory leaks

[Nielsbishere]

Describe the bug There's a few minor memory leaks regarding Qt and general destructors.

To Reproduce Checkout feature_fix_memleak_2 in WispRenderer. Launch Maya; attach VS; take capture of allocations. Load plugin; unload plugin; take capture of allocations.

Expected behavior Should clean up; but leaks ~30 MB CPU.

Screenshots System (please complete the following information): N.A.

Additional context This thread will include all findings of memory leaks.

[Nielsbishere]

~RenderPipelineSelectCommand is not being called; other than that, I found that some Qt elements were allocated somehow; which may or may not be because of the plugin.