Added all items from CIS Section 7 Levels 1 & 2

https://benchmarks.cisecurity.org/tools2/ubuntu/CIS_Ubuntu_12.04_LTS_Server_Benchmark_v1.0.0.pdf
The entry you linked is actually in relation to an entirely different task.   I didn't do it because all that command does is to force the system to immediately flush the router cache on the box and I was thinking to myself that the box would perform that action when the ami is built and launched (since this would essentially be a reboot.) 

With that said for other people who are applying this may wish the affects to be immediate in which case the route flush would be a good thing.  It can't hurt us so I will add it.  Good catch.