Layer name restrictiveness

[trasch]

In tilestrata/lib/TileLayer.js:7 is this layer name validation:

	if (!/^[a-zA-Z0-9_\-]+$/.test(name)) {
		throw new Error('Invalid layer name "' + name + '" (must match /^[a-zA-Z0-9_\-]+$)');
	}

I wonder if there is a reason that this is so restrictive and doesn't allow for example ',' (comma) or ';' (semicolon)? I think the URI spec allows them, as far as I understand it (?)