[dev] update notebooks(w/o xtensor-io); update travis

Author: Roy-Kid

.travis.yml

@@ -157,7 +157,7 @@ install:
     - export PATH="$HOME/miniconda/bin:$PATH"
     - hash -r
     - conda update -yq conda
-    - conda install -y cmake xtl==0.6.9 xtensor=0.21.2 nlohmann_json=3.7.1 -c conda-forge
+    - conda install -y cmake xtl=>0.8.0 xtensor=>0.26.0 nlohmann_json=3.7.1 -c conda-forge
     - |
       if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then
         conda install -y fftw -c conda-forge

notebooks/intensely_edgy_cat.ipynb

@@ -9,13 +9,13 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": null,
    "metadata": {},
    "outputs": [],
    "source": [
-    "#include <xtensor/xarray.hpp>    // xarrays!\n",
-    "#include <xtensor/xview.hpp>     // slice the image arrays into color channels\n",
-    "#include <xtensor/xbuilder.hpp>  // xt::stack\n",
+    "#include <xtensor/containers/xarray.hpp>    // xarrays!\n",
+    "#include <xtensor/views/xview.hpp>     // slice the image arrays into color channels\n",
+    "#include <xtensor/generators/xbuilder.hpp>  // xt::stack\n",
     "\n",
     "#include <xtensor-io/ximage.hpp> // for loading images\n",
     "\n",