More windows fixes

* fixed signed/unsigned warnings
* fixed SIGNAL() with no params warnings
* #ifdef around crash related to application startup with metavoxels


5>..\..\..\libraries\metavoxels\src\DatagramSequencer.cpp(195): warning C4018: '<' : signed/unsigned mismatch
5>..\..\..\libraries\metavoxels\src\DatagramSequencer.cpp(494): warning C4018: '<' : signed/unsigned mismatch
5>..\..\..\libraries\metavoxels\src\MetavoxelUtil.cpp(304): warning C4003: not enough actual parameters for macro 'SIGNAL'
5>..\..\..\libraries\metavoxels\src\SharedObject.cpp(207): warning C4003: not enough actual parameters for macro 'SIGNAL'