Add flattened wrapper around PraefNetworkIdentifierPair_t.
Fix inverted subtraction in stdsys.
Add utility to log system info to stderr.
Support internet games via the main menu.

Still needs a real vertex host. There's also an issue with divergence in
objects due to the way projectile collisions are handled.
Start transactor with a node count of 1, as documented.

This fixes an off-by-one with vote counting that made the stack overly
optimistic.
Fix issues with projectiles.

- Collision boundaries are now sane.

- Projectiles are actually removed when consumed.

- No more divergence.