CSS class directive not recognised as used

[palasjir]

When using class directives used css class within style is marked as unused.

Example:

<style>
.active { } // this is marked as unused by the editor
</style>

<div class:active></div>

Expected:

<style>
.hello {} // this class is used
.active { } // this class is used
.disabled { } // this class is truly unused
</style>

<div class:active class="hello"></div>

[tomblachut]

Related to #11

[tomblachut]

Will be released as part of 0.16.0