[Thomas Hurst]:
> Ideally similar strings would have identical hashes so it's a simple hash
> lookup, otherwise I might have to do some work, and we can't have that ;)

That is not possible in the general case, consider for example

	s1 = 'AAAAA'
	s2 = 'BAAAA'
	s3 = 'BBAAA'
	s4 = 'BBBAA'
	s5 = 'BBBBA'
	s6 = 'BBBBB'

Since s1 is "similar" to s2, they should have the same hash value.
Since s2 is "similar" to s3, they should have the same hash value.
....

This means that s1 and s6 will have to have the same hash value even
though they are not similar at all.

// Niklas