Add .editorconfig for file formatting

.editorconfig

@@ -0,0 +1,17 @@
+# See: http://editorconfig.org
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+# Tab indentation (no size specified)
+[Makefile]
+indent_style = tab
+
+# Matches the exact files either package.json or .travis.yml
+[*.yml]
+indent_style = space
+indent_size = 2