Msg forever in my heart

• Use S4U instead of MSG for ptasks.
• Replace all includes of msg.h by s4u.hpp (required for XBT logging)
• Remove calls to MSG_init
• Cleaned up all occurrences of Msg throughout the code

Pipeline

Branch name.

• Descriptive and short
• Use hyphens to separate words

Branch content.

• Only dedicated to the problem.
• Based on Batsim's official master branch.
• Straightforward. Just a sequence of commits. Does not contain merge commits.
• Test results are not worse than before. How to run Batsim tests?