cmp: Make memtable key comparisons ~4x faster. Similar to the internal key comparison improvement: Only parse expensive FixedInts when required. This change brings rusty-leveldb within 10% of the original for write-heavy workloads and 25% for iterating workloads.

[package]
name = "leveldb-tool"
version = "0.1.0"
authors = ["Lewin Bormann <lewin@lewin-bormann.info>"]

[dependencies]
rusty-leveldb = { path = "../../" }