Re-export IResult

@SergioBenitez: It'd be nice to not have to depend on `synom` as well.
diff --git a/src/lib.rs b/src/lib.rs
index b80934b..65ad6df 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -178,6 +178,8 @@
     //! `IResult::Incomplete` variant. The `synom` crate should be used instead
     //! of `nom` when working with the parsers in this module.
 
+    pub use synom::IResult;
+
     #[cfg(feature = "full")]
     pub use item::parsing::item;