Changed GetPositionFromGuid() to return a nullabe Vector3d

Modified the two places that currently call GetPositionFromGuid() to handle the null value instead of handling an exception. This is more in line with RemoteTechologiiesGroup "codiing style" to not throw execptions where possible.
All that matters is the conditional compilation symbol DEBUG is not set and the line of code is not compiled. Using the release configuration like you showed will not have it defined (unless someone modifies the csproj file to have the symbol set in release mode)