component flags support

Add ability to use flags.  So currently we have this
```
<vue-input :disabled="true" :required="true"></vue-input>
```

It would be nice to be able to do this
```
<vue-input disabled required></vue-input>
```
or at least (without the vue bindings/colons)
```
<vue-input disabled="true" required="true"></vue-input>
```