Fix final computation of eo1 trig functions in sgp4()

Hello,

The attached patch recomputes `sineo1` and `coseo1` after the kepler iteration converges in `sgp4()` -- previously they weren't being recomputed.  This should make almost no difference, but recomputing after the iteration has converged seems to be what the original FORTRAN code does.  See page 8 of [SpaceTrack Report No. 3](http://www.celestrak.com/NORAD/documentation/spacetrk.pdf) -- this is in the `SGP` subroutine; the iteration in the `SGP4` subroutine given on page 18 that report is different from what this library does.