Intro screen

[nczempin]

When the game first starts up, we should convey the idea that the player is in some mothership, with regular operations going on, when suddenly an alarm/distress signal comes in from the invaded colony.

Part of the text should come from issue #18, but I would like to add some fluff beforehand, simply to avoid the player missing anything from not paying attention right from the start.

[nczempin]

In f997fe60513ca1f3290e06619c702796715ae34d, I replaced the quotes with the text from issue #18 so that the general idea gets conveyed. We're still working on the details of the story (and thus the text) in issue #18.

Also, the effect that we are doing something else and we suddenly get interrupted is not nearly there. I talked to @meriland about it; perhaps we will use sounds/music to support the effect.