Image calc histeq option

The FPE (floating point exception) returned by the "ImageCalculator2DHisteqTest" is fixed by using proper input images. I also replaced the test's baseline.
More explanations are given here: 
https://www.icts.uiowa.edu/confluence/pages/viewpage.action?pageId=70846452

Now the Dashboard is clean for ImageCalculator:

 1/17 Test  #5: ImageCalculator2DHisteqTest ......   Passed    0.12 sec
 2/17 Test  #6: ImageCalc2DMult ..................   Passed    0.12 sec
 3/17 Test  #8: ImageCalc2DAvg ...................   Passed    0.11 sec
 4/17 Test  #7: ImageCalc2DDiv ...................   Passed    0.12 sec
 5/17 Test  #3: ImageCalculator2DTest2 ...........   Passed    0.12 sec
 6/17 Test #10: ImageCalc2DTestSquareRoot ........   Passed    0.11 sec
 7/17 Test  #9: ImageCalc2DTestSquare ............   Passed    0.11 sec
 8/17 Test #11: ImageCalculator3DTest1 ...........   Passed    0.13 sec
 9/17 Test #13: ImageCalc3DTestIMult .............   Passed    0.13 sec
10/17 Test #12: ImageCalc3DTestOMult .............   Passed    0.13 sec
11/17 Test #15: ImageCalc3DTestIDiv ..............   Passed    0.12 sec
12/17 Test #14: ImageCalc3DTestODiv ..............   Passed    0.12 sec
13/17 Test #17: ImageCalc2DTestOAdd ..............   Passed    0.11 sec
14/17 Test #16: ImageCalc2DTestIAdd ..............   Passed    0.12 sec
15/17 Test  #2: ImageCalculator2DGaussianTest ....   Passed    0.15 sec
16/17 Test  #1: ImageCalculator2DTest1 ...........   Passed    0.16 sec
17/17 Test  #4: ImageCalculator2DTest3 ...........   Passed    0.15 sec

100% tests passed, 0 tests failed out of 17

Total Test time (real) =   0.20 sec