qt5: 5.10 -> 5.11

This is the first time since 5.9 that we also update `qtwebkit`.
`qtwebkit` is not maintained by Qt anymore and thus, we switch to the
community port as for example arch has done. To prevent pulling in
single patches, we just stick to the latest git version.

pkgs/development/libraries/qt-5/qtModule.nix

@@ -8,7 +8,7 @@ args:
 
 let
   inherit (args) name;
-  version = args.version or srcs."${name}".version;
+  version = if (args.version or null) == null then srcs."${name}".version else args.version;
   src = args.src or srcs."${name}".src;
 in
 
@@ -53,7 +53,7 @@ mkDerivation (args // {
     homepage = http://www.qt.io;
     description = "A cross-platform application framework for C++";
     license = with licenses; [ fdl13 gpl2 lgpl21 lgpl3 ];
-    maintainers = with maintainers; [ qknight ttuegel periklis ];
+    maintainers = with maintainers; [ qknight ttuegel periklis bkchr ];
     platforms = platforms.unix;
   } // (args.meta or {});
 })