Edited the scenarios

[sevu]

Restrict other Eras from being used with the default map, because they use different recruits. However, this does also forbid the case of using another era but the modification instead.

Didn't add this to the alternative map, since you start there with two Peasants. You can't recruit new ones though if you choose e.g. Ageless Era.

Also some other changes.

[Robertdebrus]

Thanks, I had forgotten to disallow other eras. You start with two peasants, but you need ANLEra to actually do and building of keeps. Thanks!