Added hirak/prestissimo for travis

Author: webysther

.travis.yml

@@ -12,6 +12,8 @@ php:
 script:
   # Update composer to latest version.
   - composer self-update || true
+  # For faster installing
+  - composer global require hirak/prestissimo
   # Validate composer.json file.
   - composer validate
   # Try to install all requirements.