Nimrod and nawak fixes

- Update to latest Nimrod
- As far as I could test, the problems that happened on ec2 (https://github.com/TechEmpower/TFB-Round-9/blob/master/ec2/linux/final/latest/logs/nawak/err.txt) and peak (https://github.com/TechEmpower/TFB-Round-9/blob/master/peak/linux/final/latest/logs/nawak/err.txt) shouldn't happen anymore. *Please confirm!*
- Nawak now has multi-thread workers instead of multi-process workers. This should improve performance in all areas.