Handle malformed feeds

[avivace]

A malformed, interrupted or bad-formatted feed usually crashes the feed parser

[dennib]

Addressing this in 16bc4c1 :

FeedParseDone was called with an error on every parse-related error occured during feed parsing process and inside of it we were forcing the bot to crash with

function feedParseDone(err, rows) {
    log(rows, 1)
    if (err) {
        log(err, err.stack, 0);
        return process.exit(1);
    }
}

With last changes we're now avoiding the crash simply logging "an error message" in correspondence of the problematic feed (Full error stack available with logging level 1).

function feedParseDone(err, rows) {
    log(rows, 1)
    if (err) {
        log('Error on feed...', 0);
        log(err, err.stack, 1);
    }
}

A "cooldown" system for problematic feeds is surely still required but at least the bot can continue to work properly checking the other ones.

I've been testing this for some days now, seems to run flawlessly :P