python-six: added as a new dependency

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@74469 15284696-431f-4ddb-bdfa-cd5b030d7da7

.travis/linux.install.sh

@@ -38,5 +38,6 @@ sudo apt-get install --no-install-recommends \
     dpatch \
     libblas-dev \
     liblapack-dev \
-    python-numpy
+    python-numpy \
+    python-six
 

Dockerfile

@@ -54,6 +54,7 @@ RUN apt-get update \
         python-numpy \
         python-pil \
         python-ply \
+        python-six \
         sqlite3 \
         subversion \
         unixodbc-dev \

REQUIREMENTS.html

@@ -173,6 +173,10 @@ newer versions are named "python-pillow"
 <a href="http://matplotlib.org/">http://matplotlib.org/</a>
 </li>
 
+<li><b>Python six Library</b> ("python-six", needed for Python API)<br>
+<a href="https://github.com/benjaminp/six">https://github.com/benjaminp/six</a>
+</li>
+
 <li><b>Python wxPython backend for python-matplotlib</b> ("python-matplotlib-wx", needed for e.g. g.gui.timeline)<br>
 <a href="http://matplotlib.org/">http://matplotlib.org/</a>
 </li>