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/screenshot.cpp b/layers/screenshot.cpp
index 202cb85..fe4b770 100644
--- a/layers/screenshot.cpp
+++ b/layers/screenshot.cpp
@@ -384,10 +384,10 @@
 
 static const VkLayerProperties ss_device_layers[] = {
     {
-        "ScreenShot",
+        "screenshot",
         VK_API_VERSION,
         VK_MAKE_VERSION(0, 1, 0),
-        "Layer: ScreenShot",
+        "Layer: screenshot",
     }
 };