chore(conventions): EditorConfig for consistent coding styles

Closes angular-ui#1609

.editorconfig

@@ -0,0 +1,18 @@
+# This file is for unifying the coding style for different editors and IDEs
+# editorconfig.org
+
+root = true
+
+[*]
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+# Tabs in JS unless otherwise specified
+[**.js]
+indent_style = space
+indent_size = 2
+
+[*.md]
+trim_trailing_whitespace = false