Add form options for each step

[fullpipe]

Sorry for looooooong response.
Rebased. Test added.

[coveralls]

Coverage decreased (-0.14%) to 99.24% when pulling 73a9c56 on fullpipe:step_form_options into 4d14115 on craue:master.

[coveralls]

Coverage decreased (-0.14%) to 99.25% when pulling 5df513f on fullpipe:step_form_options into 4d14115 on craue:master.

[craue]

I totally forgot about your original PR already. 😄 I'm going to close #172 in favor of this one because it's much more powerful.

I'd prefer calling them "form options" rather than just "options" to clarify what they are, i.e. please rename options to form_options, $options to $formOptions, and setOptions/getOptions to setFormOptions/getFormOptions.

[craue]

Either the type hint or the is_array check can be removed. Having both is useless. I'm tending slightly into removing the type hint to be consistent with the type handling of the other setters.

[coveralls]

Coverage decreased (-0.75%) to 98.64% when pulling 179f6af on fullpipe:step_form_options into 4d14115 on craue:master.

[coveralls]

Coverage decreased (-0.75%) to 98.64% when pulling 179f6af on fullpipe:step_form_options into 4d14115 on craue:master.

[coveralls]

Coverage increased (+0.01%) to 99.39% when pulling 179f6af on fullpipe:step_form_options into 4d14115 on craue:master.

[craue]

$formOptions please. The string for the step config should be 'form_options' like you did, but not the property.

[craue]

I'm seeing one issue with this now: What should happen if one option is defined in all three possible places, e.g. validation_groups? Should they be merged (somehow) or should they be overwritten in a specific order? And I guess both approaches make sense (depending on the use case). Thus I'll not close #172 but merge it as well to provide an easy way to just add validation groups, while this PR will simply overwrite options (including the generated step-specific validation group).

[craue]

@fullpipe: But you just need to fix those two remaining commit comments. I'll rebase, squash, merge then.

[coveralls]

Coverage decreased (-0.14%) to 99.25% when pulling 4ad628f on fullpipe:step_form_options into 4d14115 on craue:master.

[craue]

Thank you, @fullpipe.