coverter_to_threejs.py: two new options and removed trailing whitespaces

Removed trailing whitespaces and added options I myself use, one in order to prevent the script from trying to copy the texture files and another to force the y axis to always be up (so when z is the up axis in the model, as is the default when working with 3ds Max in conjunction with AutoCad, it changes that so the y axis shows up as is common in real-time graphics). At first I thought about adding an option to choose the choose the up axis but then it's not likely anybody is ever going to use this since three.js is designed for y showing up.