Namespace aliases are not returned

When we try to retrieve the namespace aliases in the FileReflector we
have noticed that we did not receive any results despite that there are
namespace aliases present in a file.

During a previous refactoring the concept of a DocBlock Context was
introduced but the getters for namespace and namespace aliases were
not changed to retrieve their information from that context class.

In this commit I have altered the FileReflector to use the context and
I have cleaned up a few parts.

This change fixes phpDocumentor/phpDocumentor#1313.

Author: mvriel

src/phpDocumentor/Reflection/FileReflector.php

@@ -49,34 +49,37 @@
  */
 class FileReflector extends ReflectionAbstract implements PHPParser_NodeVisitor
 {
+    /** @var string An MD5 hashed representation of the contents of this file */
     protected $hash;
-    protected $contents = 1;
-    /**
-     * @var IncludeReflector[]
-     */
+
+    /** @var string The contents of this file. */
+    protected $contents = '';
+
+    /** @var IncludeReflector[] */
     protected $includes = array();
-    /**
-     * @var ConstantReflector[]
-     */
+
+    /** @var ConstantReflector[] */
     protected $constants = array();
-    /**
-     * @var ClassReflector[]
-     */
+
+    /** @var ClassReflector[] */
     protected $classes = array();
-    /**
-     * @var TraitReflector[]
-     */
+
+    /** @var TraitReflector[] */
     protected $traits = array();
-    /**
-     * @var InterfaceReflector[]
-     */
+
+    /** @var InterfaceReflector[] */
     protected $interfaces = array();
-    /**
-     * @var FunctionReflector[]
-     */
+
+    /** @var FunctionReflector[] */
     protected $functions = array();
+
+    /** @var string The name of the file associated with this reflection object. */
     protected $filename = '';
+
+    /** @var DocBlock */
     protected $doc_block;
+
+    /** @var string The package name that should be used if none is present in the file */
     protected $default_package_name = 'Default';
 
     /** @var string[] A list of markers contained in this file. */
@@ -88,8 +91,8 @@ class FileReflector extends ReflectionAbstract implements PHPParser_NodeVisitor
     /** @var string[] A list of all marker types to search for in this file. */
     protected $marker_terms = array('TODO', 'FIXME');
 
-    protected $namespace_aliases = array();
-    protected $current_namespace = '';
+    /** @var Context */
+    protected $context;
 
     /**
      * Opens the file and retrieves its contents.
@@ -453,12 +456,12 @@ public function getParseErrors()
 
     public function getNamespace()
     {
-        return $this->current_namespace;
+        return $this->context->getNamespace();
     }
 
     public function getNamespaceAliases()
     {
-        return $this->namespace_aliases;
+        return $this->context->getNamespaceAliases();
     }
 
     public function getContents()