Fixing some issues in the cpu-last script

The script had not work properly, because I used a regular expression,
now I only count the length of the cpu-last value. When it counts less
than 4 chars the script adding an 0 before the first char.
Adding a script which outputs the focused window

With i3-py it was very easily possible to output the focused window.
The script expects two possible Parameters (title, class). With the
'title' parameter it is possible to output the title of the window, with
the 'class' parameter the script is printing the Xorg-Class of the
focused window.
Now to prevent content jumping I adding a Zero to the CPU-last number
Switching to alsa -> Rewriting the mute script