Function healpixNestIndex( k, ra, dec )

Description:
Gives the pixel index for a given sky position in the HEALPix NEST scheme.
Parameters:
k (integer)
resolution parameter - log to base 2 of nside
ra (floating point)
right ascension in degrees
dec (floating point)
declination in degrees
Return Value (long integer):
pixel index
Signature:
long healpixNestIndex(int, double, double)