Add support to recursive transform block coding

This commit re-designs the bitstream syntax to support recursive
transform block partition. The initial stage targets the inter
prediction residuals.

Change-Id: I556ab3c68c198387a2fd2d02e2b475e83cd417c3
diff --git a/configure b/configure
index 456f7c2..8bb20b7 100755
--- a/configure
+++ b/configure
@@ -264,6 +264,7 @@
     spatial_svc
     fp_mb_stats
     emulate_hardware
+    var_tx
     ext_tx
     misc_fixes
     ext_intra