When run-time isn't early enough, do it at build-time

• Introduces a HTMLBars transform to ensure that every step has a name, and that the step-manager always has an initial value. This prevents the case where the steps are registered at runtime, but too late in the rendering process to be able to update the parent without causing double-updates. With this build-time assistance, all of the required information exists on the first render, alleviating the previous issue of the render not finishing until the second pass. This also means that Fastboot should work "out of the box", showing the initial step when it's requested.
• Dropped the ability to access an array of step names; this will also have to be determined at build time (see the double-update problem mentioned above) and it just not an immediate priority.
• Adds the ability to revert back to the initial step when binding the currentStep to a query param.

v0.8.0

• Remove the initialStep attribute
• Add a currentStep attribute that can be one- or two-way bound, which is useful for syncing the current step to a query param

v0.7.0

• Transition from on-transition to did-transition and will-transition
• Change the arguments of those actions to always be { value, from, to }, so that the consumer can pick out the data that they care about

v0.6.0

• Expose currentStep (the name of the currently active step)
• Update how the on-transition action is called, so that it's arguments are always value, fromStep, toStep

v0.5.0

• Major refactoring to the underlying transition mechanism
• Expose totalSteps

v0.4.0

• Remove requirement for steps to have names

v0.3.0

• Removes requirement of providing the initial step name