Adding integration test framework along with 3 tests.

These tests are similar to Go unit tests except that they're targetting
tesing of a running cAdvisor client. They do this by interacting with
the testing framework that is able to talk to the running cAdvisor. This
cAdvisor could be local or remote.
Fix raw driver's setting of CPU mask.

We used to include it with the trailing "\n" which gave us parsing
errors in the UI (and the reason why they didn't show up in any of those
containers).
Let the raw driver handle the /docker container.

This will give us stats on this container and since the /docker UI
endpoint, it no longer serves the purpose it once did.
Memory stats should not be omited if empty.

They may be zero. Also removed Limit from MemoryStats, that belongs in
MemorySpec and is there today. All info requests return the spec.
Merge pull request #318 from vmarmol/fix-cpuset

Fix raw driver's setting of CPU mask.
Merge pull request #319 from vmarmol/omitempty-stats

Memory stats should not be omited if empty.
Merge pull request #321 from vmarmol/docs

Add a case in the docs for the / bindmount error.
Merge pull request #317 from vmarmol/integration

Adding integration test framework along with 3 tests.
Merge pull request #320 from vmarmol/docker-raw

Let the raw driver handle the /docker container.
Remove unused code.
Removing contributors file since it is always out of date and GitHub has a better record anyways.
Merge pull request #322 from vmarmol/cleanup

Misc cleanups
cAdvisor 0.6.2
Merge pull request #324 from vmarmol/release

cAdvisor 0.6.2
Register inotify watches on all cgroup hierarchies.

We used to only register them on the first hierarchy that was created (I
think this was unintentional). This caused some weird edgecases where
we'd try to delete a watch event we didn't create. It is an error we
ignore today (since we fix it in < 60s) but delays our destruction of
the container.
Merge pull request #326 from vmarmol/integration

Register inotify watches on all cgroup hierarchies.
Ignore update errors for dead containers.

This adds an Exists() interface to detect when the container is dead.
Before reporting an update error we check is Exists() is true.

Some documentation was added as well.
Update testify dependency.
Merge pull request #327 from vmarmol/deps

Update testify dependency.
Added missing space to README.md