allow ls_files to take a subdirectory argument

Author: bryanlarsen

lib/git/base.rb

@@ -426,8 +426,8 @@ def update_ref(branch, commit)
     end
 
 
-    def ls_files
-      self.lib.ls_files
+    def ls_files(location=nil)
+      self.lib.ls_files(location)
     end
 
     def with_working(work_dir) # :yields: the Git::WorkingDirectory

lib/git/lib.rb

@@ -293,9 +293,9 @@ def diff_index(treeish)
       hsh
     end
 
-    def ls_files
+    def ls_files(location=nil)
       hsh = {}
-      command_lines('ls-files', '--stage').each do |line|
+      command_lines('ls-files', ['--stage', location]).each do |line|
         (info, file) = line.split("\t")
         (mode, sha, stage) = info.split
         file = eval(file) if file =~ /^\".*\"$/ # This takes care of quoted strings returned from git