Added editorconfig

IDEs like PhpStorm 8 support it natively.

Borrowed from https://github.com/cakephp/cakephp/blob/master/.editorconfig

.editorconfig

@@ -0,0 +1,21 @@
+; This file is for unifying the coding style for different editors and IDEs.
+; More information at http://editorconfig.org
+
+root = true
+
+[*]
+end_of_line = lf
+
+[*.php]
+indent_style = space
+indent_size = 4
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.bat]
+end_of_line = crlf
+
+[*.yml]
+indent_style = space
+indent_size = 2