Fix live trading for GDAX (and others) add a message to improve low v…

…olume pre-roll (DeviaVir#470)

* Show a message now while waiting for first live trade

* Fixing pre-roll trade_cursor for exchanges that don't paginate on timestamps

commands/trade.js

@@ -115,11 +115,10 @@ module.exports = function container (get, set, clear) {
               limit: 1000
             }
             if (db_cursor) {
-              trade_cursor = db_cursor
               opts.query.time = {$gt: db_cursor}
             }
             else {
-              trade_cursor = query_start
+              trade_cursor = s.exchange.getCursor(query_start) 
               opts.query.time = {$gte: query_start}
             }
             get('db.trades').select(opts, function (err, trades) {
@@ -262,6 +261,10 @@ module.exports = function container (get, set, clear) {
                 }
                 if (s.period) {
                   engine.writeReport(true)
+                } else {
+                  readline.clearLine(process.stdout)
+                  readline.cursorTo(process.stdout, 0)
+                  process.stdout.write('Waiting on first live trade to display reports, could be a few minutes ...')
                 }
               })
             })