Implementation of stellar aberration

See the sci ops talk:

Update 4/15/2008

• astro::GPS::aberration():
  for given position in the sky, return correction. Used by toSky and LATdirection
• astro::GPS::enableAberration(bool set);
  must be called to enable inclusion of the aberration. Invoked by FluxSvc::
   
• astro::GPS::toSky()
  for converting LAT coordinates to celestial: apply aberration if enabled. Used by:
  • AnalysisNtuple::McCoordsAlg (HEAD only)
  • AnalysisNtuple::ObfCoordsAlg (HEAD only)
  • AnalysisNtuple::FT1Alg ( since  GR v13p9)
     
• astro::GPS::LATdirection()
  Used by simulation to generate the LAT direction given an celestial coordinate. Should be used by
  • flux::FluxSource -- not implemented!
  • flux::SourceDirection -- not implemented!
     
• FluxSvc::FluxSvc, property EnableAberration
  • not defined yet (code lost)