Change CI flows

restrict builds to only specific branches
use composer without prefer-source

.travis.yml

@@ -7,6 +7,11 @@ php:
   - 5.5
   - 5.6
 
+branches:
+  except:
+    - /^3\..*$/
+    - /^scrutinizer-.*$/
+
 matrix:
   fast_finish: true
 
@@ -30,7 +35,7 @@ before_install:
   - echo "extension=zmq.so" >> ~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/travis.ini
   - yes | pecl install imagick
 install:
-  - travis_retry composer install --optimize-autoloader --dev --prefer-source
+  - travis_retry composer install --no-progress --no-interaction --optimize-autoloader
   - travis_retry npm install
 before_script:
   - mysql -e 'CREATE DATABASE update39_test;CREATE DATABASE ab_test;CREATE DATABASE db_test;SET @@global.sql_mode=STRICT_ALL_TABLES;SET @@global.max_allowed_packet=33554432;SET @@global.wait_timeout=999999;'