New function bindings

New bindings to the following functions: fits_delete_file, fits_open_table, fits_open_image, fits_open_data,
fits_file_name.
New HDU functions

New functions: fits_movabs_hdu, fits_movrel_hdu, fits_get_num_hdus
Documentation updated
New functions: fits_get_num_rows, fits_get_num_rowsll, fits_get_num_cols, fits_read_col
Merge pull request #1 from ziotom78/master

New function bindings for opening/deleting files and for moving through the HDUs of a file