Upgrading tests to PostgreSQL 9.5 (brianc#1114)

Setting PostgreSQL 9.5 as the main version to test against. NOTE: The following settings are required for 9.5 to work: ``` sudo: required dist: trusty ```

Author: vitaly-t

.travis.yml

@@ -1,5 +1,6 @@
 language: node_js
-sudo: false
+sudo: required
+dist: trusty
 before_script:
  - node script/create-test-tables.js pg://postgres@127.0.0.1:5432/postgres
 env:
@@ -16,16 +17,16 @@ matrix:
  include:
  - node_js: "0.10"
  addons:
- postgresql: "9.4"
+ postgresql: "9.5"
  - node_js: "0.12"
  addons:
- postgresql: "9.4"
+ postgresql: "9.5"
  - node_js: "4"
  addons:
- postgresql: "9.4"
+ postgresql: "9.5"
  - node_js: "5"
  addons:
- postgresql: "9.4"
+ postgresql: "9.5"
  - node_js: "6"
  addons:
  postgresql: "9.1"
@@ -38,3 +39,6 @@ matrix:
  - node_js: "6"
  addons:
  postgresql: "9.4"
+ - node_js: "6"
+ addons:
+ postgresql: "9.5"