Update to bitmap font to honor newlines

I'm building some GUI objects and I needed line wrapping, I didn't think extending was the way to go for this 

If the string passed to the bitmap font engine has a \n it will start a new line art 125% of the font height. Combine this with a wordwrap function and you have nice paragraph text

Shouldn't affect anyone currently using bitmapFont, but MeasureText() will need to be rewritten to return the correct size in the future.