Fixed issue 1 (#7)

postBuild

@@ -5,7 +5,8 @@ python download_cache.py
 mkdir ~/.fonts
 wget http://antiyawn.com/uploads/Humor-Sans-1.0.ttf
 mv Humor-Sans-1.0.ttf ~/.fonts/Humor-Sans-1.0.ttf
-fc-cache -fv -y ~/.fonts
+cd ~/.fonts/
+fc-cache -f -v
 
 # run matplotlib once to generate the font cache
 python -c "import matplotlib as mpl; mpl.use('Agg'); import pylab as plt; fig, ax = plt.subplots(); fig.savefig('test.png')"