Change some annotations
• Change startup beheaviour of the application:
  If a second instance will be started the window of the first instance
	will be toggled (and not shown). Now, it's possible to map the
	toggle-window shortcut on the same key binding as the
	(external) application start.
• Add new config file option: show_on_startup
Add system wide search for config file and asset folder. This is
a preparation for the install option in Makefile.
Add install and unistall option to Makefile
Anpassung des READMEs
Swap selected build types between all and release target