Add an editorconfig

Fixes #15

.editorconfig

@@ -0,0 +1,17 @@
+# EditorConfig is awesome: http://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+# Unix-style newlines with a newline ending every file
+[*]
+charset = utf-8
+end_of_line = lf
+indent_style = tab
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+# Ignore .md files, because 2 spaces at end-of-line has meaning
+[*.md]
+trim_trailing_whitespace = false