Support Formatted Text + Html

[Axemasta]

Add support for formatted text so that a user could provide HTML and have it render in a label using a FormattedString

Usage

 <Label FormattedText="{mocale:Localize MyHtmlKey" />

with the translation:
"MyHtmlKey" : "Hello <strong>World</World>

Rendering a formatted string along the lines of:

<Label>
    <Label.FormattedText>
        <FormattedString>
            <Span Text="Hello " />
            <Span FontAttributes="Bold" Text="World" />
        </FormattedString>
    </Label.FormattedText>
</Label>

Might be a bit difficult to get totally right, but worth a punt!