Open to implement for milestone v1.0

[Marc Aschmann]

To implement before v1.0

• ansible-galaxy integration for automated install/upgrade of needed plugins (optional)
• Override for timeout default in factory
• Refactor e.g. sudo() to have optional parameters (true). Makes imeplementation in php-deploy easier
• Implement parameter analyzer for --extra-vars to be able to input either string or array of options
• centralize parameter string/array checks
• abstract shell_exec() for proper UnitTesting
• use proper english in README
• add sf versions 2.6/2.7 to travis tests
• flexible/configurable timeout for process component