testutilities: Make RandomMatrix() more random

Delete default parameter for function and create
overload that passes seed from time in total
seconds.
test/transformation_chain: Use new RandomMatrix()

Use the new and more random RandomMatrix()
function to have a more random and better test.
testutilities: Description for relative checking

Improve the docs for `IsMatrixEqual()` and
`IsVectorEqual()` + explain why used relative
checking in function bodies and not absolute.