MAINT: Update itertools dep to 0.7.0

Author: bluss

Cargo.toml

@@ -32,7 +32,7 @@ version = "0.1.32"
 default-features = false
 
 [dependencies.itertools]
-version = "0.6.1"
+version = "0.7.0"
 
 [dependencies.rustc-serialize]
 version = "0.3.20"