Rotational Constructor - 14

The rotational constructor is mostly finished. The grid is completely implemented and working. After I finally had all the graphical stuff done it was rather easy and straight forward. I have now decided that the angle constraint takes precedence over the grid.

I don't call it finished for one small detail. Currently the texture for the grid is 64x64 pixels and that means that the distances between the lines are not all the same. It is the most compatible choice as all OpenGL implementations can handle power of 2 textures. What I still plan to implement is to check, if I can use non power of two textures and in that case make the texture 100x100 pixels. I think it is worth it as I can see the differences in distance clearly.