BatchSender: upping limit for good browsers

It finally happens...

SDPI sends a lot of metrics, and only fitting about one event per batch is harming performance. This change will increase to about 10 events per batch.

IE will still suffer, as usual.
It needs to be to support Bower which is what most Rally Angular projects are using. Unless you're saying remove builds/rallymetrics.js and keep builds/rallymetrics.min.js?