fix gtk.Application to Gtk.Application, change src folder name
add data folder content
add the src files
write toolbar.py
application condition if window exists
write player.py
write window.py
some fixes for window and player
write view.py
correct syntax error 

shivani@shivani:~/gnome-music-python/gnome-music$ python3 application.py 
  File "application.py", line 19
    if(!self._window):
       ^
SyntaxError: invalid syntax
fixed syntax errors in application windows and player.
syntax errors fix in window and player
Updated .gitignore
application: avoid null
application: remove unused import