[#87]: Remove hyphen from sektion's UID

It serves no purpose and can only cause confusion should a student
forget to type the hyphen
If columnifying, then shouldn't the columns be emptied first?
Treat .single-line when its within a .modal
[#75]: Added controller action and model method to merge two Account objects together

For now, only Accounts for Students can be merged. Going forward, who knows,
we might need to merge other roles too
[#75]: Allow teachers to add students whilst allowing students to register seprately

Teachers can create a sektion and populate it with students by
providing just their names. But we do not require spreadsheet upload - as
the issue required

Students, however, can register seprately and enter the sektion's UID.
If they don't , then they wouldn't see their graded assignments. The choice is now theirs

But if they do, then the account created by them during registration is merged
with the account created when the teacher added the student's name

Please note that this is only the initial commit. Bug fixes should be
expected and will follow
Merge branch 'master' of github.com:abhinavc/web-application

Conflicts:
	app/assets/stylesheets/bootstrap-overrides.css.scss