Fixing renderscript uniform binding bugs.
Working on custom shaders.

Change-Id: I0d51e879e1c2b46ef5ab696b35162898f4196fc8
diff --git a/rsVertexArray.cpp b/rsVertexArray.cpp
index 001927c..075a70d 100644
--- a/rsVertexArray.cpp
+++ b/rsVertexArray.cpp
@@ -129,7 +129,7 @@
 
     rsc->checkError("VertexArray::setupGL2 disabled");
     for (uint32_t ct=0; ct < mCount; ct++) {
-        uint32_t slot = 0;
+        int32_t slot = 0;
 
         if (mAttribs[ct].name[0] == '#') {
             continue;
@@ -150,6 +150,9 @@
                 continue;
             }
         }
+        if(slot < 0) {
+            continue;
+        }
 
         //logAttrib(ct, slot);
         glEnableVertexAttribArray(slot);