Automatic closing of the sexa when reaching limit

[Fredrik]

First step: disable it Second step: do it automatically

[Fredrik]

Disable sexa preference, and default to false

This disables the possibility to register for the sexa.

Refs #92

→ <<cset 0126b9e38eaa>>

[Fredrik]

Apparently the sexa should be opened again

[Fredrik]

Enable sexa preference again, and raise limit

Refs #92

→ <<cset 9b202a993e99>>