Docs: Final cleanup for CDD source.

   - Fix rowspan in table in section 2.1.
   - Put markdown links on a single line.
   - Escape parentheses in URLs.
   - Fix some internal links with dashes instead of underscores.
   - Replace tabs with spaces.
   - Other misc. cleanup.

Bug: 32070486
Change-Id: Ie44202b5a0bfe7133505880a0a9c74f08a9bac1f

CDD: Add section on performance consistency.

Android 7.0 introduces new APIs that allow the top foreground
application to reserve exclusive cores and request sustained
performance across a prolonged period.

While the support of such features itself are not required
universaly, the new section describes when and how device
implementations can declare support for these features.

Bug: 28917134
Bug: 27858072

Change-Id: I06c92d45baf65849b7ec528885d7621013278d62

CDD: Power-saving mode, S3 and S4 updates.
Bug: 28119993

Change-Id: I9f33b9ea26f7780eb2acb70e79b0192f2c6099bf

Docs: Add CDD docs and the build script, and test examples

Bug: 25199595
This is based on the amended final CDD for M, hosted as commit
1846a9622485855d572705a7972116caf0be3669 on the AOSP master branch.

Change-Id: Ic3bd96cd652f7d7b13def03a4ca1f04645c34255