Measurements API

[lukastruemper]

This is the first step to cleaning up and generalizing the tuning API:

• A method to robustly measure runtimes in a subprocess. The sub-process can be killed with a timeout which is very useful for tuning when you've already searched good candidates.
• Methods to sample random arguments, create data reports and create arguments from data reports
• An additional parameter to compile which does not copy the SDFG. Everytime we call the sub-process measure, the SDFG gets copied, so this saves time when searching large search spaces