minX1 should be max(-maxD,0) not max(maxD,0), avoid black band at left
Reworked documentation building to work with extra modules.

The main problem with extra modules is that they're located outside
of the OpenCV root, while Sphinx requires that all documents are
within the documentation root. To circumvent this, we create a
"fake root" and copy all documentation (as well as all files that
it depends on) there. It's a bit messy, but what can you do.

As a bonus, this eliminates the need to generate modules/refman.rst
inside the source tree.
Initial NativeCamera support for Android 4.4 KitKat.
Prebuilt libnative_camera_xxx updated.
added INTER_AREA interpolation to ocl::resize
Removed all slashes after ${OpenCV_INSTALL_BINARIES_PREFIX}.

If it's followed by a slash and OpenCV_INSTALL_BINARIES_PREFIX is empty,
then the resulting path becomes absolute.

Fixes <http://code.opencv.org/issues/3350>.
workaround for ocl::absSum (eliminated error: unreachable executed)
fixed memory leak in ogl::Texture2D
Android NDK r9b support added.
Merge pull request #1821 from SpecLad:watch-your-slashes
Merge pull request #1825 from jet47:fix-opengl-mem-leak
Merge pull request #1823 from ilya-lavrenov:ocl_abs_sum
Merge pull request #1820 from asmorkalov:android_native_camera_44
added area fast mode to ocl::resize
Merge pull request #1787 from hs3180:2.4
Merge pull request #1793 from SpecLad:external-docs-1
Merge pull request #1827 from asmorkalov:android_ndk_r9b
Merge pull request #1819 from ilya-lavrenov:ocl_resize_AREA