Auto-close for iselse, isbreak, and iscontinue need to be disabled

Given the following snippet:

```
<isif condition="foo">
  // …
<iselse/>
  //...
```

If you type `<` Sublime will close the `iselse` as `</iselse>`when it should close `isif` as `</isif>`.

Also, tags like `<iscontent />` and `<isset />` need to be handled without auto-closing.
