Housekeeping.

Removed all the complete old mess of the outdated Plugin Loader
The new generic loader is ready and can be used.
Move all shared Interfaces into Contracts for my own sanity.
In the process move more tests not needed anymore.

Author: LoneWandererProductions

CommonLibraryGuiTests/CommonLibraryGuiTests.csproj

@@ -58,8 +58,6 @@
     <ProjectReference Include="..\ImageCompare\ImageCompare.csproj" />
     <ProjectReference Include="..\InterOp\InterOp.csproj" />
     <ProjectReference Include="..\LightVector\LightVector.csproj" />
-    <ProjectReference Include="..\PluginLoader\PluginLoader.csproj" />
-    <ProjectReference Include="..\Plugin\Plugin.csproj" />
     <ProjectReference Include="..\RenderEngine\RenderEngine.csproj" />
     <ProjectReference Include="..\Solaris\Solaris.csproj" />
   </ItemGroup>

CommonLibraryGuiTests/Image/example Polaris.png

@@ -93,7 +93,6 @@
     <ProjectReference Include="..\InterOp\InterOp.csproj" />
     <ProjectReference Include="..\LightVector\LightVector.csproj" />
     <ProjectReference Include="..\Pathfinder\Pathfinder.csproj" />
-    <ProjectReference Include="..\PluginLoader\PluginLoader.csproj" />
     <ProjectReference Include="..\RenderEngine\RenderEngine.csproj" />
     <ProjectReference Include="..\Serializer\Serializer.csproj" />
   </ItemGroup>