Make "OnNewStep" its own subStep type

[Al.B]

Currently, if you create a step type and name it OnNewStep, it will execute when an instance of the step is created.  This is pretty confusing to new users - why don't we just have an OnNewStep substep type (like prestep, edit, etc)? Custom steps would then just be meant to be called manually using the Step.ExecuteSubstep() Method as documented in the help.

We could keep the "onNewStep" custom step functionality to maintain backwards compatibility with older step types. 

[Al.B]

The first sentence should be:

Currently, if you create a custom substep within a custom step type and name it OnNewStep, it will execute when an instance of the step is created.