Merge pull request #26 from nikicat/master

network_mode support, bugfixes
Bump version: 4.1 → 4.2
entities.Image: add possibility to customize docker client host for all methods
actions: use SourceImage for ambassador container
actions: build and push images before starting containers remotely
actions: rename "ambassador" function to "getambassador"
actions: fixed "build" command according to Image class changes