Finishing chk_solar_term (not tested yet!)

* To finish it, I had to change gzadag for first of duplicated days
  from gzadag[0]-1;60,0 to gzadag for the second of duplicated days
  and I updated the printing functions
Merging all test header files
Small adjustments (renaming solar term function and adding in header)
Finishing get_solar_term, seems to work fine!
Small adjustment of sun factor in case of non-Sherab Ling system