add emplyment history, educational history, skills and attachment fieldsets
Improves fieldset usage.
Refactors application form

* Uses one fieldsets per model.
* Add new models (Education)
* Uses form collections (ZF2 Feature)
added Fieldnames for educations, skills and employments
Test form rendering via view helpers. Add (localized) datepickers to date fields.
New form element "date range".

add Element-Classes, ViewHelper, Javascript and CSS-Files.
Add and remove items in form collections.
Improve Application form. Split Skills fieldset. Merge NativeLanguage and Language.

* Nicer selectboxes using jqueryui.selectmenu widget.
* Bugfixes in form submit handler (in work).
Optimize Hydrator strategies for Mappers and Form-Fieldsets.
Merge branch 'feature/additional-form-fields' into develop