Timeout if no connection

[decay29]

So, if I run the temperature example and do not connect a thermometer within about a minute I get

error 1570640902.713533: Error on line: 296 (src/blestatemachine.cc): Operation now in progress terminate called after throwing an instance of 'std::logic_error' what(): Trying to read socket while connecting Aborted

In my own code, I catch the exception and reconnect, but then it seems to give up after the second attempt.