add .editorconfig edtor configuration file

this is an editor configuration file that is agnostic of the actual
editor being used.

See http://editorconfig.org/

.editorconfig

@@ -0,0 +1,19 @@
+# This file is for unifying the coding style for different editors and IDEs
+# editorconfig.org
+
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 4
+
+[*.json]
+indent_style = space
+indent_size = 4
+
+[*.txt,wp-config-sample.php]
+end_of_line = crlf

.gitignore

@@ -2,6 +2,8 @@
 \.*
 # include .gitignore (i.e. do NOT ignore)
 !.gitignore
+# include .editorconfig (i.e. do NOT ignore)
+!.editorconfig
 # ignore all files that start with ~
 ~*
 # ignore css generated by Sass