Linting tutorial and rebuild dev website (#216)

* Linting tutorial [build:website_dev]

* Fixing linting

* Adding snappy to pip

* Adding testpath to deps

* [build:website_dev]

.travis.yml

@@ -1,4 +1,4 @@
-sudo: false
+sudo: true
 language: generic
 os:
   - linux
@@ -74,7 +74,9 @@ jobs:
 
     - <<: *package_test
       env: DESC="Test package on pip"
-      script: doit test_user_install_part2_pip
+      script:
+        - sudo apt-get install snappy
+        - doit test_user_install_part2_pip
 
     - <<: *package_test
       os: osx

examples/tutorial/05_Composing_Plots.ipynb

@@ -288,8 +288,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "import colorcet as cc\n",
-    "from colorcet.plotting import swatch, swatches #noqa: imported for use in exercises"
+    "import colorcet as cc\n"
    ]
   },
   {
@@ -298,6 +297,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "from colorcet.plotting import swatch\n",
     "swatch('CET_L4')"
    ]
   },

setup.cfg

@@ -57,6 +57,8 @@ install_requires =
     selenium
     # inadvertent dependency of streamz
     ipywidgets
+    # unstated dependency of datashader?
+    testpath<0.4
 
 [options.extras_require]
 tests =