Adds a new experiment CONFIG_NON420 that allows other chroma subsamplings
to be passed to the codec. This commit allows the data to be passed from
a y4m input file through vpxenc to the codec, where they're currently
rejected. Later commits will finish support for this inside the codec.

Change-Id: Ib3aac604d8cad9e24cef395fa1067f16ba7e8e43

Approximate the Google style guide[1] so that that there's a written
document to follow and tools to check compliance[2].

[1]: http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml
[2]: http://google-styleguide.googlecode.com/svn/trunk/cpplint/cpplint.py

Change-Id: Idf40e3d8dddcc72150f6af127b13e5dab838685f

Changes 'The VP8 project' to 'The WebM project', for consistency
with other webmproject.org repositories.

Fixes issue #97.

Change-Id: I37c13ed5fbdb9d334ceef71c6350e9febed9bbba

When the license headers were updated, they accidentally contained
trailing whitespace, so unfortunately we have to touch all the files
again.

Change-Id: I236c05fade06589e417179c0444cb39b09e4200d

Change-Id: Ieebea089095d9073b3a94932791099f614ce120c

A large collection of example files may be found at
 http://media.xiph.org/video/derf/
This also fixes a bug in ivfenc for uncompressed IVF input, which previously
 appeared not to skip past the file header the second time it opened the file.
I don't actually have an IVF file with which to test this fix, however.

Change-Id: Id69a1e11a3fa16c4a4fa8944e880bcea090cd52b