Integrate KIST socket/circuit scheduling

This ticket is a parent for tracking work needed to implement/test/simulate/integrate the new global scheduling and write-limiting techniques for handling kernel output. This is funded by Sponsor F.

The initial design is from Rob's USENIX Security 2014 paper entitled "Kernel-Informed Socket Transport", which will be available here: http://www.robgjansen.com/publications/kist-sec2014.pdf and the appendices here: http://www.cs.umn.edu/tech_reports_upload/tr2014/14-012.pdf