removed admin_pages, we have separeted namespaces for admin stuff
added validation to semester model (issue #8)

fixed typo in semester's attribute name
added semesters controller for creating valuation semesters (#8)
created valuation model and updated schema information comments (issue #8)
controller for editing valuation (issue #8)

members can only update the scholarship_index
fixed typo in member_post
valuation editing for community and professional requirements (#8)
checking valuation period on every request in the controller (#8)