Submit jobs before checking status

[donkirkby]

Particularly when reprocessing old runs, the number of active jobs can dip well below the configured maximum. It looks like the queue gets full, then the find_samples() thread notices that it's been over an hour since it scanned for new runs, and it has to recheck all the samples in the active run folders. It's also checking the status of all the active samples between each sample recheck, so it can take over an hour to finish the rescan.

Suggested fix: don't check the status of active samples, if a new sample has just been added, and maybe use a larger queue for folder events.