added missing contrib & legacy chapters to the reference manual; fixed (x, y)->(y, x) ordering in Mat.at (ticket #1726)

added logo to the online docs
moved quick-search panel
added logo with white sign

updated some more links

updated docs links in tutorials

updated links in cheatsheet
renamed directory for Mat tutorial 
changed links from willow docs to opencv.itseez.com, from Trac to current Redmine

changed OpenCV version to 2.3.2

modified highgui and ts modules and cmakelists for ios cross-compiling, added ios toolchains, added ios build tutorial

Added the "Camera calibration With OpenCV" tutorial. Extended with a few global links the conf.py file. Corrected an error in the linux_install.rst and one in the cascade_classifier.rst file. 

Added the "How to write a tutorial for OpenCV?" tutorial. Made some corrections to the feature2D TOC tree. Small visual improvements for the video-write.rst file. Deleted a definition file that served no purpose.