[qcms] Make half float code self-contained: add halffloat.h

[qcms] Make half float code self-contained: add halffloat.h

What is says on the tin. Move the half float code and data tables out of
transform utilities and into their own file.

BUG=491784
Committed: https://crrev.com/da8ec4a1a7d36de6f0ad1c34739f2f15a750be2a
Cr-Commit-Position: refs/heads/master@{#336311}

[Noel Gordon, 2015-06-25 16:44:45]

noel@chromium.org changed reviewers:
+ mikelawther@chromium.org

[Mike Lawther (Google), 2015-06-26 01:18:13]

On 2015/06/25 16:44:46, noel gordon wrote:

lgtm

[Mike Lawther (Google), 2015-06-26 01:18:19]

The CQ bit was checked by mikelawther@chromium.org

[commit-bot: I haz the power, 2015-06-26 01:18:58]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1206353002/1

[commit-bot: I haz the power, 2015-06-26 01:23:25]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-26 01:24:12]

Patchset 1 (id:??) landed as
https://crrev.com/da8ec4a1a7d36de6f0ad1c34739f2f15a750be2a
Cr-Commit-Position: refs/heads/master@{#336311}