loader: More changes for gh181

With Piers' fix, another path was broke because we still needed
to intercept the call before it went to the ICD.  Now, with his
change and this change, all paths work.

Also, clean up some code based on comments from Ian and Courtney
reviews.

Finally, update docs to indicate behavior of new loader 3
interface with ICDs.

Change-Id: I2d3f962baffb21c1edeb93b132ffad40f298c8e7
diff --git a/loader/table_ops.h b/loader/table_ops.h
index 427a7f6..546273f 100644
--- a/loader/table_ops.h
+++ b/loader/table_ops.h
@@ -541,7 +541,7 @@
         return (void *)table->CmdExecuteCommands;
 
     if (!strcmp(name, "CreateSwapchainKHR")) {
-        // For CreateSwapChainKHR we need to use the entry and terminator
+        // For CreateSwapChainKHR we need to use trampoline and terminator
         // functions to properly unwrap the SurfaceKHR object.
         return (void *)vkCreateSwapchainKHR;
     }