Add SoulseekQt.app 2017-7-29 Release Candidate (#4508)

* Add SoulseekQt.app 2017-7-29 Release Candidate

* soulseek-rc

Casks/soulseek-rc.rb

@@ -0,0 +1,13 @@
+cask 'soulseek-rc' do
+  version '2017-7-29'
+  sha256 '2ccc407192e91a3a15ab60214e1799145434d666251e801b540701c406825758'
+
+  # dl.dropboxusercontent.com/s/jx7790ztbn147ko was verified as official when first introduced to the cask
+  url "https://dl.dropboxusercontent.com/s/jx7790ztbn147ko/SoulseekQt-#{version}.dmg"
+  name 'Soulseek'
+  homepage 'https://www.slsknet.org/'
+
+  depends_on macos: '>= :mavericks'
+
+  app 'SoulseekQt.app'
+end