Add a disk map to machine info.
This is read once at start of cAdvisor. We can use this to report
machine state as well as return logical name for block devices in UI.

Signed-off-by: Rohit Jnagal <jnagal@google.com> (github: rjnagal)
Merge pull request #368 from rjnagal/diskinfo

Add a disk map to machine info.
Better handling of empty filesystems.
Caches container info for 5 seconds before updating it
Merge pull request #367 from kateknister/master

Caches container data for 5 seconds before updating it
Merge pull request #369 from vmarmol/fix

Better handling of empty filesystems.
Handle old versions of the libcontainer config.

Libcontainer recently changed its config by changing the type of a
field. This commit tries parsing the config as the new and old types.
Merge pull request #370 from vmarmol/old-libcontainer

Handle old versions of the libcontainer config.
Add testify/require to godeps
Refactoring Docker integration test.

Uses assert and require. Moves common components to a common file for
reuse.
cAdvisor 0.7.0.
Merge pull request #373 from vmarmol/release

cAdvisor 0.7.0.
Merge pull request #372 from vmarmol/integration3

Refactoring Docker integration test.
Add cpu frequency to machine info.