StreamlineFlow updated

added comments, still can't figure out how the ODE trick quite works. It
seems to solve a normalized electric field, over a series of angles,
appends each integration step result to an array for that angle. It
checks each step if it has exited the plotting area or has hit a charge.

The thing that I don't get is how scipy ODEs and integrator works, also
I don't get how does it _not_ plot something _every_ time. After all
plt.plot() is not inside any kind of if, and even weirder it seems to
work just fine....