Merge pull request #8 from ZlayaZhaba/master

Docker REST API enabled for Ubuntu by default (port 4243)
Narrow down exception; remove unused code
Reduce sleep time to 20 seconds before instance config and move out of repeat cycle
Move templated envs resolving to instance method
Move keyname generation to provider's method
Add extra space for docker cmd
Deal with dependencies exceptions
Fix json template escape quotes
Place Deploy exception back when cannot install dependencies
Fixing typo for aptitude