[spec&factory] request specs for School Levels
[spec] trait :master for school factory
add option to destroy school level nested attributes under school
little school controller refactor
[view] beautification for school_level nested form
change requiring nested_form gem from admission to core
Merge branch 'develop' of https://github.com/kalkov/GAKUEngine into develop

Conflicts:
	core/app/views/gaku/admin/schools/show.html.slim
[helper] comma_separete_list take block to modify how element are added
add applicant number to admission index
fixing problems with helper methods
Merge remote-tracking branch 'tapalilov/develop'