Major Changes

• No longer purges '' and 0 values - 59e6265
• Minimum Node version upped to 4.x
  _It still works with 0.10, but, if you're still using this version, it's time to move on...

Updates

• Include benchmarks
• Use tape instead of ava
• Run Travis with Nodes 6 & 8 only
• Simplify test fixtures