More rc.conf tweaks.
First cut at logic to automatically expand filesystem to fill SD on first boot
Refine the growfs script a little bit
Make swap file on first boot as well; configure growfs and makeswapfile through rc.conf
Tweaks to the autosizing config
Fix misnamed vars in makeswapfile; apply default values properly; run just before regular addswap runs
Fix default value substitution
Make swapsize more self-documenting
I do not know how to fix this bug, but I can at least document that it needs two boots to complete.
Use md entries in fstab for memdisk rather than tmpmfs in rc.conf.  Go ahead and disable sendmail.