Renamed all standard sequences (e.g. cur->c) and made them globally changeable

Renamed all standard sequences (e.g. cur->c) and made them globally changeable
The full list:
	cur -> c
	first -> f
	last -> l
	next -> n
	prev -> p
	all -> a
	new -> b (mnemonic: one beyond the last)
They are globally changeable in config/config.c
Could be that I'll add the old names again, as convenience aliases.