Fix failure in php5.3 and upgrade travis conf

This commit resolve the problem with php 5.3 compatibility and upgrade the configuration of travis-ci

Author: Gianluca Arbezzano

.travis.yml

@@ -15,7 +15,7 @@ before_script:
 script:
     - vendor/bin/phpunit
 
-branches:
-  only:
-    - master
-    - develop
+matrix:
+  fast_finish: true
+  allow_failures:
+    - php: 7

README.md

@@ -1,6 +1,7 @@
 phpctags
 ========
-[![Build Status](https://travis-ci.org/vim-php/phpctags.svg)](https://travis-ci.org/vim-php/phpctags)
+Master  [![Build Status](https://travis-ci.org/vim-php/phpctags.svg)](https://travis-ci.org/vim-php/phpctags?branch=master)  
+Develop [![Build Status](https://travis-ci.org/vim-php/phpctags.svg)](https://travis-ci.org/vim-php/phpctags?branch=develop)  
 
 An enhanced php [ctags](http://ctags.sourceforge.net/) index file generator
 compatible with http://ctags.sourceforge.net/FORMAT.

tests/Acceptance/AcceptanceTestCase.php

@@ -259,7 +259,7 @@ private function getSourceFileLineContent($filename, $line)
     {
         $filename = $this->testDir . DIRECTORY_SEPARATOR . $filename;
         $line--;
-
-        return rtrim(file($filename)[$line], PHP_EOL);
+        $file = file($filename);
+        return rtrim($file[$line], PHP_EOL);
     }
 }