[win32] add JsonSchemaBuilder.bat to the windows specific build tools
prepare xbmc.json's addon.xml for auto-generation
[win32] extend JsonSchemaBuilder.bat to auto-generate xbmc.json's addon.xml
[depends] auto-generate xbmc.json's addon.xml
Merge pull request #4662 from Montellese/jsonrpc_addon_versioning

json-rpc: auto-generate xbmc.json/addon.xml
[musicdb] drop unused function