adding editorconfig to enforce PSR-2

.editorconfig

@@ -0,0 +1,16 @@
+# This file is for unifying the coding style for different editors and IDEs
+# editorconfig.org
+
+# PHP PSR-2 Coding Standards
+# http://www.php-fig.org/psr/psr-2/
+
+root = true
+
+[*.php]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 4
+