2.3.dev1 release

TO UPDATE THE MODULE TYPE THIS IN COMMAND PROMPT
pip install -U --pre kandinsky

Fix shortcut commands not work
Fix window icon not show
add an message to user when script is finished
fix bug in get_pixel()
fix bug in draw_string() with some escape characters
add ion implementation for get_keys() method and ion-numworks module
add new button to Help menu to see the correspondence between the keys of numworks and pc
fix some display issues of GUI on Linux
handle multiple import of library
fixed bug when open directory after take screenshot on some linux distribution, is open web browser instead of file explorer
fixed game resuming after taking a screenshot while paused

TODO:
at random time, error loop when window closed in python shell mode on Windows
parameter font of draw_string() for Upsilon not implemented for moment
screen refresh stops when user interact with the GUI on Windows
calculate speed for upsilon and omega methods