don't boot the interfaces by default

that way you can f around with it easier in IRB
bunch of changes

- rename adapters -> interfaces
- require ENV variables set up correctly or bail
- add some inflection rules ("slice" -> "slouse"? lol)
- tip history!
- fix bug in User#check_available_balance!
- get 'learn' command and tipping in units working
- be anal and rename 'tx' -> 'txn'
- add indices on the tables