We shouldn't need to install the tray icons
Alternative to renaming tray icons

  It seems the icons are only really used through *qrc*, I don't really see why
we would need to install them at all. So this commit really just removes the
install instructions in CMake

  If merged, this should resolve issues #76 and #71.
Merge pull request #104 from gamaral/issue_76

We shouldn't need to install the tray icons