v1.4.0

New commands:
- `play` a log file
  commit 9b8e54263579ca48ce093727862a1a80d1102d3c
- `decode` a CAN message
  commit 431bfb723b7e6fee64cfab7c2d0017031603b845
- `clear` the screen
  commit 3b1c488242196740e6feaa034d3a4f5e17fa558d

Other new features:
- save history
  commit 33e8af0d2b023b17b6c2a8d3bd3eb3a17e776e39
- --execute
  commit 0f606f84b7d2e9af7929f05d027ebca7ca542d1f
- filter tab completion suggestions for include
  commit 7cb6b7550a73f3c86834cc0550f48f06e41ac1b8
- updated cantools to handle extended vs standard frame correctly
  commit 7725400faecd5eaf81ef37f5ef6623a06a6062f9
- show available/selected CAN bus at start up
  commit 2c2f1fbe8311aca01dcbc2802dcfff6b5858d520

Bugfixes:
- don't crash when passing an invalid value to a signal in send
  commit 8ee78955c161cb19528a6976b1010ca99f74bb29
- read: timestamp can be timedelta or None, too, depending on parsed log format
  commit d7f6627b7d2a459f5ea418864635c026d4cba46f
- don't indent help
  commit b87e465aae1c08a83ccc27cfb847048a66bc071f