parafac test suite compares wrong

[fredrikbk]

The parafac test suite compares a tensor to expected data by comparing two sets of values. This results in equality comparison which is too fragile for floating point values. There's also the problem that it doesn't compare values at specific locations in the tensor, just checks that each value exists in the expected set.

I recommend we store expected result as a tensor with some data. Then the result tensor can be compared to the expected tensor with the friend bool equals(const TensorBase&, const TensorBase&); function.

[fredrikbk]

For now I removed the test in 3d3617e . Comment it back in when this issue is fixed.