Functionality of IO_kernel/function3d.f90 is tested.
In IO_kernel/function3d.f90, several bugs are fixed. In Modules/westcom.f90, an array named nlq is added to contain nl's of different q points. In IO_kernel/pdep_db.f90, I use write_function3d subroutine to output eigenpotentials to file and I use read_function3d immediately to read eigenpotentials from files. Difference are computed. In Wstat/davidson_diago.f90, I compute nl for each q point. A lot of printing sentences for test purpose are in function3d.f90 and pdep_db.f90. This needs to be removed. The format of function3d.f90 is a little bit messy,which needs to be well organized later.