Calculate synchronization accuracy within the chull module

Move the linear programming-based synchronization accuracy code from the eval
module to the chull module. This avoids having to break the chull module
encapsulation to access the hull points from the eval module. As before,
accuracy information is only available if the glpk library is available at
build time.

Signed-off-by: Benjamin Poirier <benjamin.poirier@polymtl.ca>