Merge branch 'jl/submodule-ignore-diff'

* jl/submodule-ignore-diff:
Add tests for the diff.ignoreSubmodules config option
Add the 'diff.ignoreSubmodules' config setting
Submodules: Use "ignore" settings from .gitmodules too for diff and status
Submodules: Add the new "ignore" config option for diff and status

Conflicts:
diff.c

diff --cc Documentation/config.txt
Simple merge

diff --cc Documentation/diff-options.txt
Simple merge

diff --cc builtin/commit.c
Simple merge

diff --cc diff.c
index bf65892f78f84a31b6bf87b0f82cfc5938485862,1ddfdfbc2cf0e147cd5991d022fb16736389d4eb..ccc9f1f64d094b1943c905f4060dce555745d48b
--- 1/diff.c
--- 2/diff.c
+++ b/diff.c
@@@ -2819,7 -2820,8 +2826,7 @@@ static void run_checkdiff(struct diff_f
  
  void diff_setup(struct diff_options *options)
  {
-       memset(options, 0, sizeof(*options));
+       memcpy(options, &default_diff_options, sizeof(*options));
 -      memset(&diff_queued_diff, 0, sizeof(diff_queued_diff));
  
        options->file = stdout;