more documentation on legendre
new common function interface gsl_sf_legendre_array_norm
rename functions: ...array_norm... -> ...array...
added deriv/deriv2 for spherical harmonics
added documentation on deriv2
added fully normalized ALFs + more documentation
added unnormalized functions + docs
added ALF news
moved legendre routines to a _source format
changed deprecated INCLUDES -> AM_CPPFLAGS in makefiles
minor fix in legendre docs
various tweaks to legendre files
remove legendre_on/off.h
forgot to commit some files
better dx computation for legendre tests
tests for deriv_alt
fix array indices in loop
deprecated the functions:
  gsl_sf_legendre_Plm_array
  gsl_sf_legendre_Plm_deriv_array
  gsl_sf_legendre_sphPlm_array
  gsl_sf_legendre_sphPlm_deriv_array
  gsl_sf_legendre_array_size

They have been marked with GSL_DISABLE_DEPRECATED macro; docs updated
minor doc updates for legendre functions
fixes to unnormalized legendre
added unnormalized legendre deriv2 function