qLibs++ is widely compatible with most Arduino cores including 8bit architectures. To install the qLibs++ package into your Arduino IDE you can use the Library Manager (available from IDE version 1.6.2). Open the IDE and click to the "Sketch" menu and then Include Library > Manage Libraries.

Then the Library Manager will open and you will find a list of libraries that are already installed or ready for installation. Type in the search box "qlibs" and when listed, click the install button. Once it has finished, an Installed tag should appear next to the library. You can close the library manager.

You can now find the new library available in the Sketch > Include Library menu.