Move ComparisonNumber into the library and add an OwnedLiteral for booleans.

src/parser/parser.rs

@@ -123,6 +123,11 @@ pub enum OwnedLiteral {
     LPositiveInteger(u64),
     LNegativeInteger(i64),
     LFloat(f64),
+    // Unlike the other OwnedLiterals, booleans cannot occur in DustJS
+    // templates because true/false are not reserved
+    // names. Regardless, they are needed here for type casting in the
+    // renderer.
+    LBoolean(bool),
 }
 
 #[derive(Debug, PartialEq)]