* kmeans: number of channels in _centers fixed

* fixedType() is checked now

- fixed returned compactness value
- added centers drawing to the example app
- added compactness test

trying to solve compile problems; temporarily disabled some tests for just added optimization algo's

reshape input matrix, since the function works with data
as with [N x dims] matrix

Fixed a valgrind 'Conditional jump or move depends on uninitialised value(s)' on cv::kmeans(...). The original code used points(sampleCount, 1, CV_32FC2), which confused generateCentersPP into thinking it is a 1 dimensional center, instead of 2. As a result it would set only the x variable and leave y unitialised.
(cherry picked from commit 601b7d1d)

Fixed a valgrind 'Conditional jump or move depends on uninitialised value(s)' on cv::kmeans(...). The original code used points(sampleCount, 1, CV_32FC2), which confused generateCentersPP into thinking it is a 1 dimensional center, instead of 2. As a result it would set only the x variable and leave y unitialised.