Started working on user-defined-fields for all entities (references #176)

localization/en/userfield_types.php

@@ -0,0 +1,11 @@
+<?php
+
+return array(
+	'text-single-line' => 'Text (single line)',
+	'text-multi-line' => 'Text (multi line)',
+	'number-integral' => 'Number (integral)',
+	'number-decimal' => 'Number (decimal)',
+	'date' => 'Date (without time)',
+	'datetime' => 'Date & time',
+	'checkbox' => 'Checkbox'
+);