DSL improvements: make phase parameters optional

[Rafael Bagmanov]

Genesis "parser" should automaticly discover phase by order of step declaration in case of
phase and preceding phase parameters not being present.

for instance:

instead of:

            provisionVms {
                phase = "provision"
                roleName = "erlangNode"
                hardwareId = "1"
                imageId = "5825"
                quantity = nodesCount
                retryCount = 3
            }
            chefrun {
                phase = "install"
                precedingPhases = ["provision"]
                roles = ['erlangNode']
                runList = ["recipe[erlang]"]
            }

it should be possible to declare:

            provisionVms {
                roleName = "erlangNode"
                hardwareId = "1"
                imageId = "5825"
                quantity = nodesCount
                retryCount = 3
            }
            chefrun {
                roles = ['erlangNode']
                runList = ["recipe[erlang]"]
            }

NOTE: If phase is absent the ("step name" + step number) should be used as phase value

TODO: discovering rules should be more clarified here.

More complex sample

[Svyatoslav Reyentenko]

Closed with merge 811a6a2