Remove earthquake and make falling slower and more realistically

This should fix https://bugzilla.gnome.org/show_bug.cgi?id=707939.
Blocks now fall slower and somewhat realistically and bounce on impact.
This happens instead of the earthquake-shaking of all blocks on impact.
Fix issue with pre filled Lines

https://bugzilla.gnome.org/show_bug.cgi?id=708073
https://bugzilla.gnome.org/show_bug.cgi?id=708074
The pre-filled rows settings could only be used until a game had started.
And it could be set too high. Fixed by giving a magic upper limit not
depending on a started game.