Improve error reporting

[unwriter]

A lot of .env related errors are not handled precisely and the app ends up stopping with errors such as:

BITBUS all finished at block undefined
/usr/local/lib/node_modules/bitbus/block.js:46
      fileStream.write("]")
                 ^

TypeError: Cannot read property 'write' of undefined
    at Stream.<anonymous> (/usr/local/lib/node_modules/bitbus/block.js:46:18)
    at Stream.emit (events.js:203:15)
    at Stream.stream.destroy (/usr/local/lib/node_modules/bitbus/node_modules/through/index.js:84:12)
    at _end (/usr/local/lib/node_modules/bitbus/node_modules/through/index.js:67:14)
    at Stream.stream.end (/usr/local/lib/node_modules/bitbus/node_modules/through/index.js:74:5)
    at Stream.onend (internal/streams/legacy.js:42:10)
    at Stream.emit (events.js:203:15)
    at drain (/usr/local/lib/node_modules/bitbus/node_modules/through/index.js:34:23)
    at Stream.stream.queue.stream.push (/usr/local/lib/node_modules/bitbus/node_modules/through/index.js:45:5)
    at Stream.end (/usr/local/lib/node_modules/bitbus/node_modules/through/index.js:15:35)

The error report needs to be much better so the developer knows what exactly is going wrong.