The greedy search method improves the BD-rate over the baseline by
more than 0.2% for lowres test set. Larger gain 0.55% is observed for hdres test set.

[2017.04.06] Cleanup to remove redundant computation. On a local linux
machine, the greedy method is now faster than the trellis method in
encoding the first 100 frames of foreman_cif. However, the BD-rate seems
to become smaller due to the recent changes to the codebase.
[2017.04.06-2] Style changes to meet the requirements.
remove "greedy-optimize-b" in configure
[2017.04.10] Move the changes under the macro USE_GREEDY_OPTIMIZE_B
[2017.04.11] Adjust rdmult to accommodate CpuSpeedTest
[2017.04.12] Set USE_GREEDY_OPTIMIZE_B to 0 at the request of debargha@.
[2017.04.13] Move greedy implementation of optimize_b into a separate
function with the same name (selected by USE_GREEDY_OPTIMIZE_B, default
is 0)

Change-Id: Ic15534f8d696d5f02e8f2e3e9f08b52e41e9efd2