Minor correction on README

[johnnybubonic]

(hello, KML using 0 and 1 for xs:booleans that are clearly spec'd to be only ever either true or false...)

I hate to be that guy, but they are spec'd to evaluate to true/false. Their accepted values do in fact include 1 and 0.

Sources:
Schema 1.0 § 3.3.2.1
Schema 1.1 § 3.3.2.2

("Lexical" refers to the literals, "Canonical" refers to what they should evaluate to in the Schema spec parlance)

Sorry, I'm a huge XML/Schema nerd and that was just nibbling at my brain.