"TRUE"/"FALSE" should not be used as literals, as CMake has to decide
whether they are literals or variable names (sigh).
This patch should make it work with any version of CMake and with any
user-side decision on old vs. new policy behavior.

This reverts commit 7d91b8ef.

Fix problems on NVidia devices.

quickly corrected the previous refactoring of features2d: moved from set(SOME_PROP, val) to setSomeProp(val)

In this particular case t shadows transpose of the base class Matx:
types.hpp:1805:14: warning: declaration of ‘t’ shadows a member of
'this' [-Wshadow]

Changelog gcc 4.8: The option -Wshadow no longer warns if a declaration
shadows a function declaration.

This warning is problematic because it prevents the module
opencv_contrib/modules/ruby to pass the build process