Detect incompatible packages and show a warning message

[iatenothingbutriceforthreedays]

See #196 (comment) -> Seems like having certain editor packages installed (EasyButtons and NaughtyAttributes are two I found so far) will cause TriInspector to silently fail. Haven't looked at the implementation so I don't know what it would take for TriInspector to detect if this is the case, but it would be very helpful if it could show some warning in this case.

[TylerTemp]

My package SaintsField has a util to check which inspector is working. Maybe someone can port it here?

Code:
https://github.com/TylerTemp/SaintsField/blob/92ccccef2a1f11f5b8c2fdb7086a96bdabde58e1/Editor/TroubleshootEditor/TroubleshootEditorWindow.cs#L64