Matrix has "T" method. It should return the transposed matrix of the receiver matrix.
TransposedMatrix satisfies Matrix interface.
Transposed Matrices are created by calling "transposed.New".
Create test functions for "transposedMatrix".
Move all test files into test package.
Rename transposed/transposed.go to transposed/matrix.go.
Write tests for transposedMatrix.
Pass tests for transposedMatrix.
Merge branch 'feature/transpose'