import HTTP_PROXY, HTTPS_PROXY from profile
Merge pull request #186 from aheissenberger/feature/pull/docker-init-import-profile

docker init import  profile
Adding brew update command

'brew install docker' failed with 'Error: No available formula for boot2docker' - this was fixed by running brew update first. Instructions updated to reflect this.
Merge pull request #187 from paulmaunders/master

Adding brew update command
Merge remote-tracking branch 'upstream/master'