Refactor hal loading

This CL make the loading of RS drivers more robust by
looking up entry points in place of a structure of entry points.

It also adds framework for a version handshake.

Change-Id: Iae46bf0171785c0ca1048223816b6efc60c337ad
diff --git a/rsScriptC_LibGL.cpp b/rsScriptC_LibGL.cpp
index 5c55c6b..9304797 100644
--- a/rsScriptC_LibGL.cpp
+++ b/rsScriptC_LibGL.cpp
@@ -149,11 +149,7 @@
 
 
 void rsrDrawPath(Context *rsc, Path *sm) {
-    CHECK_OBJ(sm);
-    if (!rsc->setupCheck()) {
-        return;
-    }
-    sm->render(rsc);
+    // Never shipped in a working state
 }
 
 void rsrDrawMesh(Context *rsc, Mesh *sm) {