moved ict and nas header methods out of core; added support for nas files via variable delimiter; added ict.py and nas.py files into module.
Added option for variable names to `make_numpy`

Also added `print_header` function to Naspy object.
Added option for variable names to `make_numpy`

Also added `print_header` function to Naspy object.
Added custom variable names option to `make_numpy`
Updated to reflect new changes for v0.1.1