v0.4.0

Features

• Added a new --color=always/auto/never option which can be used
  to control hexyls color output, see #30 (@bennetthardwick)
• Use 16 colors instead of 256, see #38

Changes

• Various speed improvements, see #33 (@kballard)

Bugfixes

• Proper Ctrl-C handling, see #35
• Proper handling of broken pipes (hexyl … | head)