Merge pull request #243 from noplanman/travis_improvements

Improve travis config

.travis.yml

 dist: trusty
 sudo: required
+language: php
 
 addons:
   apt:
@@ -8,16 +9,20 @@ addons:
       - mysql-client-core-5.6
       - mysql-client-5.6
 
-language: php
+cache:
+  directories:
+    - $HOME/.composer/cache
 
 php:
   - 5.5
   - 5.6
   - 7.0
+  - nightly
   - hhvm
 
 matrix:
   allow_failures:
+    - php: nightly
     - php: hhvm
   fast_finish: true
 
@@ -28,11 +33,8 @@ notifications:
 git:
   depth: 1
 
-before_install:
-  - composer self-update
-
 install:
-  - travis_retry composer install --no-interaction
+  - travis_retry composer install --prefer-dist --no-interaction
 
 before_script:
   - mysql -u root -e 'create database telegrambot; use telegrambot; source structure.sql;'