Procedure: tplot_ascii Purpose: Creates an ascii file for selected tplot variables. Input: Names names of tplot variables. May use glob patterns to specify a set of variables. Keywords: fname: file name, by default 'tplot_name' where name is set to tvar[n] (variable name) Ext: by default, a separate file will be created in the current directory with name tplot_name.txt. Use this keyword to set the .txt extension to a different extension. dir: Put output in dir as opposed to current working directory. precise: increases precision to maximum trange: array[2] of double or string. Specify time range for output. header: optional keyword, if set ascii file will contain header information History: 08-Jul-2008, cg, added formating to handle 3 d data sets 09-may-2008, cg, added format statement to print so that the values didn't run together 09-may-2008, cg, added use of precision keyword, set default value = 3 29-apr-2008, cg, fixed bug with dlimits 28-mar-2008, cg, added keyword fname to allow user to specify a file name (thm_ui_dproc procedure determines and passes the filename) 28-mar-2008, cg, added file header 27-aug-2008, cg, added another time precision keyword /msec to print format 09-jul-2009, cg, added code to write the v component to a file, also added print statements indicating success or failure. 30-nov-2010, jmm, removed /msec from time_string call