library.xbmc.gui version bump ("1.0.0"->"5.0.1")

Without this patch, running iptvsimple on xbmc-git (c436c99) results in
```
23:23:49 T:139987289831168   ERROR: PVR - Add-on 'PVR IPTV Simple Client' is using an incompatible GUI API version. XBMC minimum GUI API version = '5.0.1', add-on GUI API version '1.0.0'
```