PROCEDURE erg_load_sdfit PURPOSE: Load fitacf CDF files of SuperDARN as tplot variables. :KEYWORDS: sites: 3-letter code of SD radar name. Currently only the following station codes work: 'ade', 'adw', 'bks', 'cly', 'cve', 'cvw', 'dce', 'fhe', 'fhw', 'gbr', 'hal', 'han', 'hok', 'inv', 'kap', 'kod', 'ksr', 'pgr', 'pyk', 'rkn', 'san', 'sas', 'sto', 'sye', 'sys', 'tig', 'unw', 'wal', 'zho' cdffn: File path of a CDF file if given explicitly. get_support_data: Turn this on to load the supporting data trange: time range for which data are loaded. e.g., ['2008-10-01/00:00:00','2008-10-02/00:00:00'] :AUTHOR: Tomo Hori (E-mail: horit at stelab.nagoya-u.ac.jp) :HISTORY: 2010/03/09: Created as a draft version 2010/07/01: now work for hok and ksr 2010/09/10: added some keywords