Added an editorconfig file

See https://editorconfig.org/

Author: tcalmant

.editorconfig

@@ -0,0 +1,17 @@
+root=true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+indent_style = space
+trim_trailing_whitespace = true
+
+[*.py]
+indent_size = 4
+
+[*.rst]
+indent_size = 3
+
+[.travis.yml]
+indent_size = 2