Fixed travis tests on PHP 5.5 by installing imagick manually (#148)

.travis.yml

@@ -19,6 +19,16 @@ cache:
 install:
   - travis_retry composer self-update && composer --version
   - travis_retry composer update --dev --prefer-dist --no-interaction
+  # install php extensions
+  - |
+    if (php --version | grep -i HipHop > /dev/null); then
+      echo "Skipping imagick and gmagick tests on HHVM"
+    else
+      pear config-set preferred_state beta
+      printf "\n" | pecl install imagick
+      # gmagick is not installed on travis currently
+      #printf "\n" | pecl install gmagick
+    fi
 # setup application:
   - |
     sed -i "s/'cookieValidationKey' => ''/'cookieValidationKey' => 'testkey'/" config/web.php