Add pear modules, mail and net_smtp via composer (#93)

Add pear modules, mail and net_smtp via composer, remove php 5.6 build due to phpunit 6

lib/composer/vendor/consolidation/config/.travis.yml

@@ -0,0 +1,38 @@
+language: php
+
+branches:
+  # Only test the master branch and SemVer tags.
+  only:
+    - master
+    - /^[[:digit:]]+\.[[:digit:]]+\.[[:digit:]]+.*$/
+
+matrix:
+  fast_finish: true
+  include:
+    - php: 7.2
+      env: 'SCENARIO=symfony4 HIGHEST_LOWEST="update"'
+    - php: 7.1
+      env: 'SCENARIO=symfony4'
+    - php: 7.0.11
+      env: 'HIGHEST_LOWEST="update"'
+    - php: 7.0.11
+    - php: 5.6
+    - php: 5.5
+    - php: 5.4
+      env: 'SCENARIO=symfony2 HIGHEST_LOWEST="update --prefer-lowest'
+
+sudo: false
+
+cache:
+  directories:
+    - vendor
+    - $HOME/.composer/cache
+
+install:
+  - 'composer scenario "${SCENARIO}" "${HIGHEST_LOWEST-install}"'
+
+script:
+  - composer test
+
+after_success:
+  - travis_retry php vendor/bin/coveralls -v