Add Hypercube
Add Hypercube size constructor tests
Add IsAHypercube test
Add Hypercube PartialAssignment test copied from lab instructions
Implement Hypercube in declaration
Merge branch 'hypercube'

Closes issue #1: Lab1 Extra 1.4: Hypercube
https://github.com/ZetaTwo/dd2387-laborationer/issues/1