use ASSERT_FLOAT_EQ to compare float values, it is more robust for
large values

* cmake CMP0054 and CMP0045
* aarch64 build
* portable code options in PCH cmake
* some of gcc 4.9 warnings

... before any exceptions occur.

highgui: Support to change trackbar count in setTrackbarPos and replaced deprecated CreateToolbarEx in Windows.

Fix tautologies in calibfilter.cpp which cause a build failure when using -Werror=address with clang-3.5

http://code.opencv.org/issues/4048Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>

For Bug #3714, user use the imshow() function without calling
namedWindow() properly, because user did not know the implicit rule for
imshow(). (i.e. without calling namedWindow implied calling namedWindow(
,CV__WINDOW_AUTOSIZE).

Improve the Display Image Tutorial to educate the user for such implied
rule.

Put a note on documentation for Bug#3714

Revise the documentation regarding to imshow() function to better
educate the user the implicit rule. (i.e. without creating the window
before the imshow() function is the same as creating AUTOSIZE window)

There is necessary to account also x-ccordinate of the end of the edge when determining bounding box of the edge collection.