main, glfun: adjust_rot no longer uses global vars, reset view

In a far, far away land...

Varg: ARRR, I SMELL DIRTY GLOBAL VARIABLES

Garg: Boss, should we go get 'em?

Varg: Cut 'em all down! Leave not one standing... well except when you absolutely require them.

...or something like that. I absolutely need to remove obj and migrate that to the option struct.
glfun: spherical rendering enabled

Took me a while. Turns out not many people want to render spheres, naturally. Heck, I even thought of doing a hack and exploiting the U(1) group by using a sprite. But I just took a look at what should be a very familiar integral for the reader and decided to do it myself. It's not exactly a sphere, but looks close enough at a distance. Will improve later.