custom css and js resources

allows custom css and js files to be added, these files should be placed in the css & js resource folders.
 ```xml
<custom>
        <reflowSkin>
            <cssResources>
                <cssResource>font-awesome.css</cssResource>
                <cssResource>custom.css</cssResource>
            </cssResources>
            <jsResources>
                <jsResource>custom.js</jsResource>
            </jsResources>
        </reflowSkin>
</custom>
```