Framework for the attachment system, new object property which allows changing the color and alpha of mesh materials

New object property which allows changing the color and alpha of mesh materials. Due to the current lighting systems it doesn't work yet, but the full implementation is there

Framework for the attachment system, with no actual functionality yet

Send bone and player object to the setAttachment function in content_sao.cpp, but we need a way to translate it there and send it to the client

I will also want position and rotation offsets to be possible to apply to attachments

Network object ID from server to client. This will be used to identify the parent client-side and know what to attach to