add .editorconfig

Author: m6w6

.editorconfig

@@ -0,0 +1,19 @@
+root = true
+[*]
+end_of_line = lf
+insert_final_newline = true
+charset = utf-8
+
+[*.{c,h,phpt}]
+indent_style = space
+indent_size = 4
+trim_trailing_whitespace = true
+
+[*.{yml,m4,w32}]
+indent_style = space
+indent_size = 2
+
+[package.xml]
+indent_style = space
+indent_size = 1
+