Add editor config file

.editorconfig

@@ -0,0 +1,17 @@
+# CiviCRM-WordPress editor configuration normalization.
+# @see http://editorconfig.org/
+
+# This is the top-most .editorconfig file; do not search in parent directories.
+root = true
+
+# Unix-style newlines with a newline ending every file.
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+# Indentation.
+[*.php]
+indent_style = space
+indent_size = 2