ENH: add OTB copyright as Copyright.txt

Copyright/Copyright.txt

+The ORFEO Toolbox (OTB) is developed by the French Centre
+National d'Etudes Spatiales, CNES. OTB is partially derived from ITK,
+GDAL, VTK, VXL and LibSVM, hence some code is copyrighted accordingly (see
+ITKCopyright.txt, GDALCopyright.txt, VTKCopyright.txt, VXLCopyright.txt 
+and LibSVMCopyright.txt).
+
+The OTB copyright is as follows:
+
+Copyright (c) Centre National d'Etudes Spatiales
+All rights reserved.
+
+The OTB is distributed under the CeCILL licence version 2. See
+Licence_CeCILL_V2-en.txt or
+http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt for more details.
+
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS ``AS IS''
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+