Possible fix for pg issue in node 6.x

- There is a change in `Buffer` in node 6 that causes an issue with
  authentication in the `pg`/`pg.js` modules.
- See brianc/node-postgres#1018
- Which references: brianc/node-postgres#1000
- This commit changes the pg library dependency to the version that
  contains the fix for this issue.

lib/create-common-client.js

@@ -68,7 +68,7 @@ module.exports = function (config) {
 
     } else if (config.driver === 'pg' || config.driver === 'pg.js') {
 
-        commonClient.dbDriver = require('pg.js');
+        commonClient.dbDriver = require('pg');
 
         // for backward compatibility, allows to specify port within host
         if (config.port) {

package.json

@@ -20,7 +20,7 @@
     "mssql": "2.x.x",
     "mysql": "2.x.x",
     "newline": "0.0.3",
-    "pg.js": "4.x.x"
+    "pg": "^4.5.5"
   },
   "repository": {
     "type": "git",