Change merge! to non-mutating version.
Remove Vedeu::View.
Extend minitest with some testing methods;

- 'assigns': test that an instance variable is set to a specific value.
- 'return_type_for': test that the return type of a method is a specific value.
- 'return_value_for': test that the return value of a method is the specified value.
Move file to correct directory.
Use minitest extensions, also;

- whitespace changes.