Copied errorCovPre to errorCovPost. This allows the correct behaviour of the uncertainty to grow when there is missing data for each predict step.

This should fix that pesky test failure that pops up from time to time.

I don't actually know if the default values should be zeros, but the tests
pass, so...

Looks like we don't actually use them; when creating precompiled headers
with Visual C++, a dummy .cpp is created at build time.

ReST directive was used. Also fixed some other ReST directives that were
not correct and removed some warnings during buildbot checks.

- Used lunix style slashes - works on most systems
- Removed all trailing whitespaces

This should allow many algorithms to take advantage of more parallelization
technologies.

Also cv::, cv::gpu:: and cv::ocl:: namespace prefixes can be safely omitted
inside CV_ENUM and CV_FLAGS

initial optical flow was not cleaned during the second call

* added DenseOpticalFlow interface
* moved OpticalFlowDual_TVL1 to src folder

This fixes bug #2075

Invalid links and refences fixed.
SpaeseMat class documentation updated.

issue 2526

All errors were found by doc/check_docs2.py

added recommended number of stripes to parallel_for_, modified some of the functions to use larger stripes (for better performance)