Merge branch 'feature/0.3/git-file-support' of https://github.com/igetgames/GitPython into igetgames-feature/0.3/git-file-support

Using the previous implementation of read_gitfile, but added the previously missing test from this PR.

Conflicts:
	git/repo/base.py
	git/test/test_repo.py

Author: Byron

git/test/fixtures/git_file

@@ -0,0 +1 @@
+gitdir: ./.real

git/test/test_repo.py

@@ -24,7 +24,6 @@
 
 
 class TestRepo(TestBase):
-
     @raises(InvalidGitRepositoryError)
     def test_new_should_raise_on_invalid_repo_location(self):
         Repo(tempfile.gettempdir())
@@ -615,3 +614,20 @@ def test_submodule_update(self, rwrepo):
         assert isinstance(sm, Submodule)
 
         # note: the rest of this functionality is tested in test_submodule
+
+    @with_rw_repo('HEAD')
+    def test_git_file(self, rwrepo):
+        # Move the .git directory to another location and create the .git file.
+        real_path_abs = os.path.abspath(join_path_native(rwrepo.working_tree_dir, '.real'))
+        os.rename(rwrepo.git_dir, real_path_abs)
+        git_file_path = join_path_native(rwrepo.working_tree_dir, '.git')
+        open(git_file_path, 'wb').write(fixture('git_file'))
+        
+        # Create a repo and make sure it's pointing to the relocated .git directory.
+        git_file_repo = Repo(rwrepo.working_tree_dir)
+        assert os.path.abspath(git_file_repo.git_dir) == real_path_abs
+        
+        # Test using an absolute gitdir path in the .git file.
+        open(git_file_path, 'wb').write('gitdir: %s\n' % real_path_abs)
+        git_file_repo = Repo(rwrepo.working_tree_dir)
+        assert os.path.abspath(git_file_repo.git_dir) == real_path_abs