Subzero: Make life a little easier for emacs users.

Emacs will try to execute .dir-locals.el whenever loading a file under
the subzero directory.  It sets local variables depending on the mode.

Set the fill-column to 80 for c++-mode, c-mode, and python-mode.  The
main use is when using M-q to reformat multi-line comments.

Disable tabs (use spaces instead) in c++-mode, c-mode, and
python-mode.

Set the tab-width to 2 spaces in python-mode.  (The tab-width doesn't
really matter in c++-mode or c-mode thanks to clang-format.)

BUG= none
R=kschimpf@google.com

Review URL: https://codereview.chromium.org/1199133005
diff --git a/.dir-locals.el b/.dir-locals.el
new file mode 100644
index 0000000..34e4b40
--- /dev/null
+++ b/.dir-locals.el
@@ -0,0 +1,9 @@
+(
+ (c++-mode . ((fill-column . 80)
+              (indent-tabs-mode . nil)))
+ (c-mode . ((fill-column . 80)
+            (indent-tabs-mode . nil)))
+ (python-mode . ((fill-column . 80)
+                 (tab-width . 2)
+                 (indent-tabs-mode . nil)))
+)