Fix docs build failure by re-indenting with spaces instead of tabs.

Trailing whitespace fixes. http://pullrequest.opencv.org/buildbot/builders/precommit_docs/builds/5152/steps/whitespace/logs/stdio

mingw build fix.

The "CvCaptureCAM_XIMEA::getProperty" method had not the same signature as "CvCapture::getProperty" so it was not called when we use the "VideoCapture::get" method (the "const" specifier was missing).

_sizes can point to internal structure which is destroyed
by release() call

Fixed ximea cmake settings for 32bit win build and linux.

FlannBasedMatcher::add is overloaded, but the style of parsing the
InputArrayOfArrays does not match the style from
DescriptorMatcher::add. The issue is that InputArrayOfArrays
must be properly marshalled so that the data can be read
correctly. In this case, the method expects the training
descriptors to be either a vector of matrices or a single matrix
(as is shown in DescriptorMatcher::add). These code
replicates that for the case of the FlannBasedMatcher::add.

In fact, a similar commit to this was added by 26d9a7cd but was
ultimately not accepted in #4111. This is likely due to the
fact that the input arrays were not parsed properly and the
case of a single matrix was being improperly handled. I believe
this commit to be correct given the logic from
DescriptorMatcher::add.

Very cosmetic, but was analyzing code and just wanted to make it
consistent.

Note: Force push to force a re-run of build tests. The previous tests
failed in an unrelated module. I assume it's a bug that occured
randomly.

warper.

Without fixes after 68 line (img1_filename = parser.get<std::string>(0);) OpenCV Error:
./stereo_matching im0.png im1.png --max-disparity=16 --blocksize=17

OpenCV Error: Bad argument (undeclared position 0 requested) in getByIndex, file /home/entodi/opencv/modules/core/src/command_line_parser.cpp, line 169
terminate called after throwing an instance of 'cv::Exception'
  what():  /home/entodi/opencv/modules/core/src/command_line_parser.cpp:169: error: (-5) undeclared position 0 requested in function getByIndex