Add the av1_tree_to_cdf() macro which takes a aom_tree_index tree and
 associated aom_prob probabilities and constructs a daala uint16_t cdf.
The av1_tree_to_cdf_1D() and av1_tree_to_cdf_2D() apply av1_tree_to_cdf()
 across 1D and 2D arrays respectively.

Change-Id: If79fa5ae034263f279d7d0842493570885272fb2