Merge remote-tracking branch 'upstream/master'

resolved conflicts with refactored structure

frontend/document/pdfdocument.lua

@@ -12,7 +12,6 @@ local PdfDocument = Document:new{
 	mupdf_cache_size = 5 * 1024 * 1024,
 	dc_null = DrawContext.new(),
 	options = KoptOptions,
-	configurable = Configurable,
 	koptinterface = KoptInterface,
 }