layers: Rename Layer/library/json files for consistency

Renamed layers from (for example) xxx_DrawState to xxx_draw_state
Renamed JSON files
Renamed libraries
Renamed object_track.* to object_tracker.*
Renamed apidump.h to api_dump.h
Renamed screen_shot layer to screenshot
Renamed APIDump layer settings file options to ApiDump
Bug fixes here and there from prior renames
diff --git a/layers/draw_state.cpp b/layers/draw_state.cpp
index fc42886..3483708 100644
--- a/layers/draw_state.cpp
+++ b/layers/draw_state.cpp
@@ -2887,7 +2887,7 @@
         "VK_LAYER_LUNARG_draw_state",
         VK_API_VERSION,
         VK_MAKE_VERSION(0, 1, 0),
-        "Validation layer: DrawState",
+        "Validation layer: draw_state",
     }
 };
 
@@ -2909,10 +2909,10 @@
 
 static const VkLayerProperties ds_device_layers[] = {
     {
-        "DrawState",
+        "draw_state",
         VK_API_VERSION,
         VK_MAKE_VERSION(0, 1, 0),
-        "Validation layer: DrawState",
+        "Validation layer: draw_state",
     }
 };