Feature test uqr

The test function __test_z_rot3_turnover__ tests the complex turnover. The turnover fails 1/3 of the tests for exact diagonal or exact anti-diagonal rotations. I think that the test function is correct and thus I suspect that there is a bug in the turnover code. Since we never tested the turnover for these case, our UQR algorithm deflates before they occur, it is possible. I will open an issue for this bug.
The first test that fails has a exact diagonal middle rotation.

The other test function __test_d_rot2_turnover__ tests the double turnover. The turnover passes the test.

In both cases the test function have a debug mode in which they produce a histogram of the error distribution. The plan is to use these histograms to compare different turnovers.
A single test is failed if one of the turnovers produces a matrix which deviates more than __200eps__ from the original 3x3 matrix. The whole test is further failed if the computed histogram is too much worse than the reference one.