add regression for hypertree bug (#46)

rebalance on insert would crash on uneven tree depths bc. the grand parent node would be beyond the root.
added defensive checks in rebalance for this case.

also: made verfication and debug tools accessible from fuzzer to ease integration

lib/Cargo.toml

@@ -8,6 +8,8 @@ description = "Data structures for Manifest"
 license-file = "LICENSE"
 
 [features]
+colored = ["dep:colored"]
+fuzz = ["colored"]
 trace = []
 
 [dependencies]