Refactor picker group/group box; eliminate picker.json; custom groups

This design allows custom widgets for specific groups, and uses one for
the international keys.

Author: ids1024

layouts/keysym/base.json

@@ -81,5 +81,23 @@
   "MS_WH_RIGHT": "Move wheel right",
   "MS_ACCEL0": "Set speed to 0",
   "MS_ACCEL1": "Set speed to 1",
-  "MS_ACCEL2": "Set speed to 2"
+  "MS_ACCEL2": "Set speed to 2",
+  "INT1": "INT 1",
+  "INT2": "INT 2",
+  "INT3": "INT 3",
+  "INT4": "INT 4",
+  "INT5": "INT 5",
+  "INT6": "INT 6",
+  "INT7": "INT 7",
+  "INT8": "INT 8",
+  "INT9": "INT 9",
+  "LANG1": "LANG 1",
+  "LANG2": "LANG 2",
+  "LANG3": "LANG 3",
+  "LANG4": "LANG 4",
+  "LANG5": "LANG 5",
+  "LANG6": "LANG 6",
+  "LANG7": "LANG 7",
+  "LANG8": "LANG 8",
+  "LANG9": "LANG 9"
 }