MSE test suite coverage update

Since the April F2F, editors and other contributors have made multiple
changes to the MSE portion of the wpt test suite [wpt-mse-repo] and have
uploaded more recent test results [wpt-mse-results-all].

For the MSE spec to reach PR, in addition to driving the spec bug count
down [mse-spec-issues], we will also need to demonstrate implemented
interoperability of the API across at least two UAs using the MSE portion
of the wpt test suite.

This suite needs to be updated to cover changes to the spec and known gaps.
I have begun compiling the previous analysis of test coverage
[cyrils-previous-analysis] and some similar analysis within Chromium-Blink
and shared it at [wolenetz-oct2015-preliminary-analysis] for discussion at
TPAC 2015 Media TF f2f. This more recent compilation is by no means
exhaustive, but is meant to give a more recent checkpoint for discussion
and tracking progress. Especially, any rows with colors in column B may
still require update to the wpt test suite even now.

Matt

*References:*

   - [wpt-mse-repo]
   https://github.com/w3c/web-platform-tests/tree/master/media-source
   - [wpt-mse-results-all]
   http://w3c.github.io/test-results/media-source/all.html
   - [mse-spec-issues]
   https://github.com/w3c/media-source/issues?q=is%3Aopen+is%3Aissue+milestone%3AV1
   - [wpt-test-runner] http://w3c-test.org/tools/runner/index.html
   - [cyrils-previous-analysis]
   https://docs.google.com/spreadsheets/d/1XKjIuGWjEaSvMkf31HiTaYYkLbyuNg4saP2Sf-iW-cs/edit?usp=sharing
   and
   https://lists.w3.org/Archives/Public/public-html-media/2014Dec/0012.html
   - [wolenetz-oct2015-preliminary-analysis]
   https://docs.google.com/spreadsheets/d/1XdeQm3X1eFYHBObs4sNRdpcE3mYQzVgcr-hSGxe2xBY/edit?usp=sharing