Rename HISTORY to CHANGELOG.md with better format

Follow guidelines from http://tech-angels.github.io/vandamme
and http://keepachangelog.com to help third-party sites like
Gemnasium parse the Changelog in a nicer way.

[ci skip]
Merge branch 'changelog-format'
Revert "Temporarily ignore request specs in Travis"

This reverts commit a424c3917c4511465e5b8b88da704bf4257e8485.
Revert "Temporarily ignore content-owner specs in Travis"

This reverts commit 268385a5c8b23427cecdf02b3df2f1e50348a2b3.
Don’t try to search claims for unknown videos

Supposedly YouTube API should return "No Items" or at most a "Not Found"
error when the filters for claimSearch do not match any video. Instead,
YouTube API raises a 500 error without explanation.

For now, this case is very specific and not needed, so it can be removed.
Merge pull request #63 from Fullscreen/fix-travis-tests

Fix travis tests
Remove encrypted keys from .travis.yml

When tests fail, the log file prints out the failing request in
curl format, which might contain authorization tokens that should
not be made public.

Until we have a logger level that allows us not to print out secure
information in error logs, we disable Travis on pull requests and
we run the tests manually.
Merge branch 'remove-travis-keys'
Add channel.content_owner_details