Fix problem output formatting, fixes #871

src/Composer/DependencyResolver/Problem.php

@@ -78,10 +78,10 @@ class Problem
                     $ext = substr($job['packageName'], 4);
                     $error = extension_loaded($ext) ? 'has the wrong version ('.phpversion($ext).') installed' : 'is missing from your system';
 
-                    return 'The requested PHP extension '.$job['packageName'].$this->constraintToText($job['constraint']).' '.$error.'.';
+                    return "\n    - The requested PHP extension ".$job['packageName'].$this->constraintToText($job['constraint']).' '.$error.'.';
                 }
 
-                return 'The requested package '.$job['packageName'].$this->constraintToText($job['constraint']).' could not be found.';
+                return "\n    - The requested package ".$job['packageName'].$this->constraintToText($job['constraint']).' could not be found.';
             }
         }