Improve EZSP connect logic.

[Nerivec]

Don't rely on bubbling events to handle initial "connect" logic. On error, bail and cleanup to ensure port is always available (that is if nothing else is preventing access to it of course...) then retry.
Driver will reset and try again indefinitely on failure to connect (to serial).

An example flow would look like this:

- Adapter:start
- Driver:startup
- Ezsp:connect => Try ${MAX_SERIAL_CONNECT_ATTEMPTS} times
- Driver:startup => ERROR
  - Driver:reset => Try 0
  - Driver:stop
  - Ezsp:close
  - SerialDriver:close
  - Driver:onClose
  - Driver:startup
  - Ezsp:connect => Try ${MAX_SERIAL_CONNECT_ATTEMPTS} times
  - Driver:startup => ERROR
    - Driver:reset => Pause
    - Driver:reset => Try 1
    - Driver:stop
    - Ezsp:close
    - SerialDriver:close
    - Driver:onClose
    - Driver:startup
    - Ezsp:connect => Try ${MAX_SERIAL_CONNECT_ATTEMPTS} times
    - SerialDriver:connect
    - SerialDriver:reset
    - Driver:startup SUCCESS

[Koenkk]

Awesome, thanks!

CC: @kirovilya