Print and/or connector formulas with 1 argument

Created by: cache-nez

Fixes #60.

lisa-utils/src/main/scala/lisa/utils/Parser.scala

@@ -460,6 +460,7 @@ object Parser {
       },
       {
         case ConnectorFormula(c @ (Iff | Implies), Seq(left, right)) => Seq(left ~ Some(c ~ right))
+        case ConnectorFormula((And | Or), Seq(f)) => Seq(f ~ None)
         case f => Seq(f ~ None)
       }
     )