A graphical progress bar displayed in a Tk window
progress_tk(title = "plyr progress", label = "Working...", ...)window title
progress bar label (inside window)
other arguments passed on to tkProgressBar
This graphical progress will appear in a separate window.
tkProgressBar for the function that powers this progress bar
Other progress bars:
progress_none(),
progress_text(),
progress_time(),
progress_win()