Some fixes for MongoDB example
return error if at least one container fails to start

This makes docker start exit with exit code 1 if at least one container
didn't start. This also prints an error at the end.
Fixes #1643

Changed the split statement, from SplitN to Split. Doing so takes
care of cases, when a minor version is followed by a suffix, that
starts with '.'.
Refactored code and added unit tests

- Extracted ParseRelease method from GetKernelVersion to make code
  more testable
- Added tests for ParseRelease method
Merge remote-tracking branch 'upstream/master'
Update Vagrantfile to use docker apt repository
Display error if resource not specified

Display an error message if a container resource is not supplied to
'docker cp'.

Fixes error in #1661
Change fetching of gpg key from http to https

Or was there any reason to fetch using http?
Don't force a non-existent npm version, use latest from epel

Not the smartest thing to do
Merge pull request #1646 from mohitsoni/master

- Runtime: Fix uname -r kernel version parsing
Merge pull request #1670 from tobstarr/patch-1

Change fetching of gpg key from http to https
Remove incorrect build instructions
Merge pull request #1663 from KSid/1661-cp-parsing-error

- Runtime: Display error if docker cp resource not specified
Merge pull request #1678 from dotcloud/remove-incorrect-build-instructions

Remove incorrect build instructions
Merge pull request #1636 from unclejack/1594-return_non_zero_when_encountering_error

1594 - return non-zero exit code if at least one container has failed to start
Merge pull request #1671 from kim0/patch-3

Don't force a non-existent npm version, use latest from epel
Merge pull request #1656 from KSid/vagrantfile-0.6

Update Vagrantfile to use docker apt repository
ENTRYPOINT fixups
Merge pull request #1622 from TylerBrock/patch-2

Some fixes for MongoDB example