Tweaks to tutorial and adviser texts.

Intro texts have been added to the first 7 challenges.

A button have been added to take you back to challenge selection after the challenge game is over.

When changing Hq, Fast move mode will now be taken into account. The Hqs existing move command will be replaced with a fast move command if 'shift' where held and vice versa.

Ai strike behavior have been tweak to avoid the Ai striking blindly in some rare cases.

Ai elite usage have been tweaked to better synergies with core units types.

Fixed a bug that could cause challenge replays to desync.

Fixed various Unit Deployment bugs.