I'm working with Arduino IDE 1.6.12 (my OS is ubuntu 14.04). I was trying to install the PIDAutotune library http://playground.arduino.cc/Code/PIDAutotuneLibrary by downloading the respective .zip-file from github, and then using the "Add .zip library" option in the Arduino IDE, as I have successfully done with other libraries. However, instead of installing the library, I receive the error message
"Arduino: 1.6.12 (Linux), Board: "Arduino/Genuino Uno"
Specified folder/zip file does not contain a valid library"
Does anybody know what the problem is? What do I have to do to install this library?