Merge pull request #3653 from edx/nedbat/editorconfig

An .editorconfig file to bring some sanity to indentations

.editorconfig

+# This file is for unifying the coding style for different editors and IDEs.
+# More information at http://EditorConfig.org
+
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 4
+indent_style = space
+insert_final_newline = true
+max_line_length = 120
+trim_trailing_whitespace = true
+
+[*.{yml,yaml}]
+indent_size = 2
+
+[*.rst]
+max_line_length = 79
+
+[*.mk]
+indent_style = tab
+indent_size = 8
+
+[Makefile]
+indent_style = tab
+indent_size = 8