package/opencv: bump to version 3.0

package/opencv: bump to version 3.0

This major version bump is in fact a bump from 2.4.10 to 2.4.11, then to
3.0.

OpenCV-2.4.11 improves a lot the Buildroot integration, including a
couple of patches that are no longer needed:
- x86 PIC code compilation fix in core module [1];
- return type fix in superes module [2];
- opencv.pc generation [3].

It also improves the gstreamer-0.10/1.x detection [4], that will be
needed in a follow-up patch.

OpenCV-3.0 still requires 2 patches (backported from upstream fixing
pthread support [5,6].

The OpenCV-3.0 does some major changes, for which a transition guide
has been published [7].

Among these changes coming with OpenCV-3.0, some new modules have been
introduced and others got removed; leading to a bunch of configure
option updates (to keep as much as possible an iso-functional-perimeter)
and the legacy menu has been updated too.
The worth noticing removals being:
- the opencv_legacy and opencv_nonfree modules no longer exist;
- the opencv_contrib module has moved out of the opencv base tree and
  now has its own repository [8].
  There is currently no plan to support it.

Some 3rd-party supports have been improved or added; their integrations
in Buildroot will be addressed in follow-up patches.

[1] https://github.com/Itseez/opencv/commit/ea50be0529c248961e1b66293f8a9e4b807294a6
[2] https://github.com/Itseez/opencv/commit/2e393ab83362743ba1825ad4b31d4a2925c606b4
[3] https://github.com/Itseez/opencv/commit/eceada586bbf18fc267e437522ec4f1f23ddc656
[4] https://github.com/Itseez/opencv/commit/38bb0db9dbec08666c8a64b3e4ead8fadf15c980
[5] https://github.com/Itseez/opencv/commit/1f983ec39c97298b0c8ce409a1cc229ecf14e55c
[6] https://github.com/Itseez/opencv/commit/a482dcce464acbd5368fb93c6c3d52ba8401776a
[7] http://docs.opencv.org/master/db/dfa/tutorial_transition_guide.html
[8] https://github.com/itseez/opencv_contrib

[Thomas:
  - address most contents made by Yann E. Morin on the Config.in file.]

Cc: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>