add EditorConfig support

Author: sunnywalker

.editorconfig

@@ -0,0 +1,21 @@
+# EditorConfig is awesome: http://EditorConfig.org
+
+#
+root = true
+
+# all files
+[*]
+end_of_line = lf
+insert_final_newline = true
+indent_style = space
+indent_size = 4
+charset = utf-8
+trim_trailing_whitespace = true
+
+# sass files
+[*.{scss,sass}]
+indent_size = 2
+
+# markdown
+[*.md]
+trim_trailing_whitespace = false