[Ifeffit] update to ifeffit source kit

Hi Folks, I found a serious bug in the ifeffit-1.2.11 source code kit that was on the cars.uchicago.edu and sourceforge.net sites. This bug would become readily apparent, as many operations beyond the simplest tests will not work correctly, so like any actual use of Athena would be clearly wrong. Sorry for any trouble! I uploaded a fixed source code kit (ifeffit-1.2.11a.tar.gz) to both the cars.uchicago.edu and sourceforge.net sites. This bug does not affect the Windows binaries. --Matt