Another fix for spaces in files

Based on the format of ls-tree:
<mode> SP <type> SP <object> TAB <file>
I modified the split logic to look for only one space, or a tab
character. Now it correctly handles files with leading spaces.
All other tests pass

lib/grit/tree.rb

@@ -65,7 +65,7 @@ def create_initialize(repo, atts)
     #
     # Returns Grit::Blob or Grit::Tree
     def content_from_string(repo, text)
-      mode, type, id, name = text.split(" ", 4)
+      mode, type, id, name = text.split(/ |\t/, 4)
       case type
         when "tree"
           Tree.create(repo, :id => id, :mode => mode, :name => name)

test/test_rgit_spaces.rb

@@ -38,6 +38,15 @@ def test_log_with_path_leading_space_in_a_branch
     assert_equal "36a4f6bc8c5e4e67534b98c996f4e91ffff73ea5", log.first.to_s
   end
 
-
+  def test_tree_with_leading_space
+    tree = @repo.tree()
+    names = tree.blobs.collect { |b| b.name }
+    assert names.include?(" an evil file with a leading space"), "does not contain the leading space named file"
+  end
 
+  def test_tree_with_trailing_space
+    tree = @repo.tree()
+    names = tree.blobs.collect { |b| b.name }
+    assert names.include?("an evil file with a trailing space "), "does not contain the trailing space named file"
+  end
 end