use standard string for program file path

changed member and access functions in program class
changed member and access functions in command line class

changed all functions in main window class to use program file path as a
standard string

changed version function of command line class to return standard string
(changed to static function and modified to use simple loop to find
first digit)

modified copyright statement function of command line class to accept
copyright string with default "Copyright" (GUI calls with translated
copyright string) - this allowed the translate functions to be removed
from the command line class

corrected problem in command line constructor preventing program file
argument from being interpreted

modified main window constructor when file to load does not exist (or
can't be loaded) to display a message error box (when the last file
loaded isn't found) or an error to standard error output (when command
line file isn't found)