Rework jmarray and jkmarray stuff:

    Privatise the associated structures
    Remove set and get function pointers from structs
    Auto generate int and double varieites from templates
    Split out int and double specific stuff into separate .h files
    jmarray.h and jkmarray.h contain only the idx and dim inline funcs

Fix polarizability.c and molecule_linear.c for these changes
Add asymrot_eigsys.[ch]