1.8.0

• index.js
  • replaced this.xxx with exports.xxx
    — eliminates implicit 'this' dependency that breaks when callers destructure exports
  • removed redundant ? true : false
  • same_ipv4_network: for (let i...) → for...of
  • get_ips_by_host: .map() → for...of with explicit branching
  • ipv6_reverse: function(n) callback → arrow function
  • ipv6_bogus: if (x) return true; return false → return x
  • ip_in_list: for...in → for...of over isArray ? list : Object.keys(list)
    • prevents iteration over inherited properties
• get_mx.js
  • this.get_implicit_mx → exports.get_implicit_mx
• get_public_ip.js
  • e.msg → e.message
  • return new Error(...) → console.error(...), now logs if STUN hangs
• dep(sprintf-js): removed
• deps(all): updated to latest
• remove unnecessary done callbacks, update deps #95
• test: improve coverage