GitLab

* Add gca() method to CommCompGraph
* Add is_sample() method to CombinedCommCompModel

Measured values are dots/+ and model is a curve.

Not sure if it works correctly for the show() method.

For memset when throughput is measured. Works well for bandwidth,
probably wrong for duration.

Also add a basic program to compare the behaviours when measuring
bandwidth or throughput and a Python script to generate a Paje file
from the output.

And thus remove the simple heuristic: consider only the first 20 lines as header.