build: allow bindings to class property

Previously we didn't allow binding to `[class]`, because it would override the entire `class` attribute. That's no longer the case so now we can allow it.

Author: crisbeto

tslint.json

@@ -94,7 +94,6 @@
         "Component": {
           "argument": 0,
           "properties": {
-            "!host": "\\[class\\]",
             "!preserveWhitespaces": ".*",
             "!styles": ".*",
             "!moduleId": ".*",