Merge branch 'db/checkout'

* db/checkout: (21 commits)
  checkout: error out when index is unmerged even with -m
  checkout: show progress when checkout takes long time while switching branches
  Add merge-subtree back
  checkout: updates to tracking report
  builtin-checkout.c: Remove unused prefix arguments in switch_branches path
  checkout: work from a subdirectory
  checkout: tone down the "forked status" diagnostic messages
  Clean up reporting differences on branch switch
  builtin-checkout.c: fix possible usage segfault
  checkout: notice when the switched branch is behind or forked
  Build in checkout
  Move code to clean up after a branch change to branch.c
  Library function to check for unmerged index entries
  Use diff -u instead of diff in t7201
  Move create_branch into a library file
  Build-in merge-recursive
  Add "skip_unmerged" option to unpack_trees.
  Discard "deleted" cache entries after using them to update the working tree
  Send unpack-trees debugging output to stderr
  Add flag to make unpack_trees() not print errors.
  ...

Conflicts:

	Makefile

git.c

@@ -278,6 +278,7 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "branch", cmd_branch, RUN_SETUP },
 		{ "bundle", cmd_bundle },
 		{ "cat-file", cmd_cat_file, RUN_SETUP },
+		{ "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
 		{ "checkout-index", cmd_checkout_index,
 			RUN_SETUP | NEED_WORK_TREE},
 		{ "check-ref-format", cmd_check_ref_format },
@@ -321,6 +322,8 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "merge-base", cmd_merge_base, RUN_SETUP },
 		{ "merge-file", cmd_merge_file },
 		{ "merge-ours", cmd_merge_ours, RUN_SETUP },
+		{ "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
+		{ "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 		{ "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
 		{ "name-rev", cmd_name_rev, RUN_SETUP },
 		{ "pack-objects", cmd_pack_objects, RUN_SETUP },