testframework: Enable BIL as default

Also added --no-BIL option to use built-in GLSL compiler.
diff --git a/tests/xgltestframework.cpp b/tests/xgltestframework.cpp
index 9b79396..198a23c 100644
--- a/tests/xgltestframework.cpp
+++ b/tests/xgltestframework.cpp
@@ -101,7 +101,7 @@
 // Define all the static elements
 bool XglTestFramework::m_show_images = false;
 bool XglTestFramework::m_save_images = false;
-bool XglTestFramework::m_use_bil = false;
+bool XglTestFramework::m_use_bil = true;
 int XglTestFramework::m_width = 0;
 int XglTestFramework::m_height = 0;
 int XglTestFramework::m_window = 0;
@@ -129,6 +129,11 @@
             continue;
         }
 
+        if (strncmp("--no-BIL", argv[i], 13) == 0) {
+            m_use_bil = false;
+            continue;
+        }
+
         /*
          * Since the above "consume" inputs, update argv
          * so that it contains the trimmed list of args for glutInit