[math/jrl-mathtools] Fix configure on Gentoo

Explicitly pass BLAS_LIBRARIES and LAPACK_LIBRARIES as found by robotpkg to
cmake. Also add a dependency on blas. This is needed because:

1. blas and BLAS_LIBRARIES is required on Getoo because FinBLAS.cmake is
   patched on this platform to use pkg-config. However, this breaks the
   semantics of various BLAS_* variables normally defined by the regular
   FindBLAS.cmake. Explicitly passing BLAS_LIBRARIES is sufficient in
   math/jrl-mathtools to workaround this issue, as this is the only variable
   used (indirectly by FindLAPACK).

2. Passing LAPACK_LIBRARIES is also required because of an issue with
   cmake-2.8.6. This is a different way to work around the broken
   FindLAPACK.cmake (typos) with cmake-2.8.6, and replaces the previous quirk
   consisting in distributing a FindLAPACK in ${FILESDIR}.
[interfaces/jrl-mal] Update blas and lapack variables passed to cmake

It seems that passing BLAS_LIBRARIES and LAPACK_LIBRARIES to cmake (instead of
BLAS_blas_LIBRARY and LAPACK_lapack_LIBRARY) also works for overriding cmake's
idea of blas and lacack.

In addition, this fixes some issues on Gentoo and/or with cmake-2.8.6 which
have a broken FindBLAS.cmake and FindLAPACK.cmake, respectively. See commit
9b1a367 for details.
[image/opencv] Update depend.mk for opencv>=2

The depend.mk already checks for opencv>=2.2.0, but the SYSTEM_SEARCH was still
referring to opencv1 files. Recent opencv have dropped these files, so update
SYSTEM_SEARCH.
[image/opencv] By default, use system's OpenCV
[middleware/omniORBpy] Fix depend.mk for the debian sysdep

debian omniORBpy is split into several packages, account for this in
SYSTME_PKG.Debian. Also add mandatory files in the SYSTEM_SEARCH.

At runtime, the package also needs a special PYTHONPATH in omniidl_be, so
export that too.
[image/sift] Add missing INSTALLATION_DIRS
[mk/sysdep] Add SYSTEM_PKG.Gentoo for gtk+

While here, add a <3 version constraint, since the SYSTEM_SEARCH is tuned for
gtk+-2 only.
[mk/sysdep] Drop useless license boilerplate of gtk sysdep
[image/opencv] Fix depend.mk for PREFER.opencv = system

Commit f67e0cc was wrong: old opencv headers are still installed by modern
opencv. This is just the debian package that is split in a weird manner and
both libopencv-dev and libcv-dev must be installed. Both are needed since most
of the packages using opencv never bothered with updating their includes path
to opencv2.

So re-add include/opencv in the SYSTEM_SEARCH, and while here mention the
SYSTEM_PKG names for supported platforms.
[image/ros-vision-opencv] Fix building against opencv-2.3

opencv-2.3 is still distributed on many systems (e.g ubuntu-12.04). The fix
just disables color conversions from YUV to RGB or grayscale introduced
somewhere in opencv-2.4. This is simple enough to include it and enable builds
against a system opencv on these platforms.

Dependent packages may break, though. But these should have their dependency
requirement updated.