add NFFT check macros
remove whitespace
fix macro check
rename store_points_test to nfft_test
declare *_freqs functions for testing purposes
fix segfaults due to bad pointer initialization
update descriptions and add nfft3_transform function
Fix reciprocal grid error and add NFFT functions

The reciprocal grid functions did not update the is_halfcomplex
status inside the gfunc3 structure.
Functions for NFFT transform are initially written. Need debugging
due to segfaults.
make grid_reciprocal functions reject initialized gfunc3's