introducing a tutorial for the retina model
adding retina tutorial
updated tutorial, need spell check, validation, nicer images and a discussion on parameters
updated tutorial, rapid spell check, retina parameters discussion added
added retina code tutorial
updated first image sample
minor update
minor updates for doc redirections and tutorial images size
Initial Windows RT support commit.
GPU module turned off;
TIFF support turned off;
Windows Managment and Video IO (VFW) turned off.
Multiple Windows RT fixes

TIFF build was fixed;
Direct Show back-end was enabled;
More accurate guards implemented.
More accurate guards for WinRT features in CMake.
Highgui tests for GUI disabled for WinRT;
Warnings fix;
exploring possible bug in optimize_linear_svm
add hack to disable optimization of linear svms; improved precision of optimize_linear_svm; add the relevant test, which however requires some big database (so it's disabled by default)
fixed buffer size and restored the use of compressed files in ml's load_save tests.
fixed nonfree compilation with gpu (perf tests)
updated license header in whole gpu module
Merge pull request #687 from vpisarev:fast_lin_svm2
fixed http://code.opencv.org/issues/2899
removed extra whitespaces