Use retries where applicable

.travis.yml

@@ -15,7 +15,7 @@ python:
 - 3.4
 
 before_install:
-    - tools/travis_setup.sh
+    - travis_retry tools/travis_setup.sh
 
 install:
     - python setup.py build_ext --inplace

tools/travis_test.sh

@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 set -ex
 
+
 export DISPLAY=:99.0
 export PYTHONWARNINGS="all"
 WHEELHOUSE="--no-index --find-links=http://wheels.scikit-image.org/"
@@ -13,17 +14,38 @@ flake8 --exit-zero --exclude=test_*,six.py skimage doc/examples viewer_examples
 
 tools/header.py "Install optional dependencies"
 
+#  http://unix.stackexchange.com/a/82615
+function retry()
+{
+        local n=0
+        local try=$3
+        local cmd="${@: 1}"
+        [[ $# -le 1 ]] && {
+        echo "Usage $0 <Command>"; }
+
+        until [[ $n -ge $try ]]
+        do
+                $cmd && break || {
+                        echo "Command Fail.."
+                        ((n++))
+                        echo "retry $n ::"
+                        sleep 1;
+                        }
+
+        done
+}
+
 # Install Qt and then update the Matplotlib settings
 if [[ $TRAVIS_PYTHON_VERSION == 2.7* ]]; then
-    sudo apt-get install -q python-qt4
+    retry sudo apt-get install -q python-qt4
     MPL_QT_API=PyQt4
     MPL_DIR=$HOME/.matplotlib
     export QT_API=pyqt
 
 else
-    sudo apt-get install -q libqt4-dev
-    pip install PySide $WHEELHOUSE
-    python ~/virtualenv/python${TRAVIS_PYTHON_VERSION}/bin/pyside_postinstall.py -install
+    retry sudo apt-get install -q libqt4-dev
+    retry pip install PySide $WHEELHOUSE
+    retry python ~/virtualenv/python${TRAVIS_PYTHON_VERSION}/bin/pyside_postinstall.py -install
     MPL_QT_API=PySide
     MPL_DIR=$HOME/.config/matplotlib
     export QT_API=pyside
@@ -31,20 +53,20 @@ fi
 
 # imread does NOT support py3.2
 if [[ $TRAVIS_PYTHON_VERSION != 3.2 ]]; then
-    sudo apt-get install -q libtiff4-dev libwebp-dev libpng12-dev xcftools
-    pip install imread
+    retry sudo apt-get install -q libtiff4-dev libwebp-dev libpng12-dev xcftools
+    retry pip install imread
 fi
 
 # TODO: update when SimpleITK become available on py34 or hopefully pip
 if [[ $TRAVIS_PYTHON_VERSION != 3.4 ]]; then
-    easy_install SimpleITK
+    retry easy_install SimpleITK
 fi
 
-sudo apt-get install libfreeimage3
-pip install astropy
+retry sudo apt-get install libfreeimage3
+retry pip install astropy
 
 if [[ $TRAVIS_PYTHON_VERSION == 2.* ]]; then
-    pip install pyamg
+    retry pip install pyamg
 fi
 
 # Matplotlib settings - do not show figures during doc examples