Small changes to compile for Linux

[erroreyes]

In order to compile RSBrokenMedia for Linux, I had to make a small update in Utilities.h to make an explicit reference to std::isnan. In addition, I updated the jucer file to create a Makefile for Linux. Once I made these two adjustments, I was able to compile the plugin successfully, and so far it runs well in Kubuntu and Bitwig 5.1.2.

[erroreyes]

I think that ultimately the changes to RSBrokenMedia.jucer for Linux may not be final and other Linux users may have to adjust it to point to their local Juce libs. At least they offer a starting point.

[reillypascal]

Thanks! This is helpful.