Update to the Mac OS X libspotify install

Before trying to install libspotify with brew, the user should tap into homebrew binary formulae
Merge pull request #144 from tarikd/patch-1

Homebrew moved the libspotify formula to the homebrew/binary tap
docs: Add workaround for 'image not found' (#130)
Merge branch 'v2.x/master' into v2.x/develop