Fix bugs in 3mf reader

[lvk88]

This PR addresses various runtime and compiler bugs in the 3MF IO plugin:

• 3MF import produces weird result when forcetransform is used #1610 : when meshlab is built with clang and loading a 3MF file such that Transform vertices instead of using transformation matrix is checked, the loaded objects were garbage, because of a missing zero initializer in the transformation matrix. This is now fixed
• It was not possible to build meshlab with the 3mf plugin in debug mode with MSVC 19.5, because of signed-unsigned comparison warnings that are treated as errors. This is because lib3mf defines the treat-warnings-as-errors flag and W3 error level as a PUBLIC compile option, which then propagates to consumers of the target, such as the 3mf plugin. Wherever I could fix the warnings, I did, where I couldn't, I switched it off.
• The runtime checks in MSVC's stdlib pointed out correctly that maskList was not resized to the correct size. This is also fixed
• The option "Load colors and textures" was ignored by the 3MF implementation, and color + texture data was always loaded, regardless of what the user chose. This is also fixed now
• The progress callback was not working properly because of an int-int division that should have been a double - int .

[alemuntoni]

Thank you very much @lvk88!