1) fix multichannel support
2) remove useless bad_value, read value from original Mat directly
3) add more tests
4) fix docs for cvCeil and checkRange

The original solution did not handle correctly when delta = 0,
resulting as nan errors. I also wrote a test case to test solving
equation x^3 = 0 after fixing.

some functions were not found in namespace std

calculates cube root of complex number to give more correct results.

solves equations more correctly, eliminates “nan” error.

hack solvePoly to finds roots of polynoms with zero higher-order coefficients. The roots are populated in this case, which is not valid, strictly speaking, but good enough for function like correctMatches. This solves http://code.opencv.org/issues/4330

fixed http://code.opencv.org/issues/3935
possibly fixed http://code.opencv.org/issues/3594