Made stop and drop commands more resilient.

They should not error out just because some container is no longer
present.
Merge pull request #98 from tcolar/stopdrop

Made stop and drop commands more resilient.
print stack trace on ctrl+c
Merge pull request #100 from mcellis33/stacktrace

print stack trace on ctrl+c
fixed based on new version of docker client
Merge pull request #102 from iansmith/fix_hang_on_attach_with_updated_godeps

fixed based on new version of docker client
Enable Travis-CI