add uninstall method to makefile

[Max Neupert]

sudo make uninstall
make: *** No rule to make target 'uninstall'.  Stop.

looking at the makefile I went with

sudo rm /usr/share/icons/hicolor/48x48/apps/jack-select.png 
sudo rm /usr/share/applications/jack-select.desktop 
sudo rm /usr/share/man/man1/jack-select.1
sudo rm /usr/bin/jack-select

hoping that was the right thing to do.