Add some Emacs files to .gitignore.

This ignores Emacs autosave files and any directory-local variable
files.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

.gitignore

@@ -40,3 +40,5 @@ Source/Docs/*
 # 6. IDE and code analyzer cruft
 cscope.files
 cscope.out
+*~
+.dir-locals.el