The fuzzy search score algorithm is quite simple, but had an interesting
problem: for the search string 'AB DEF', the result 'XXAXXBXXXXXXX DEF' had
a higher score than the result 'ABX X DEF", because it has 4 consecutive
matching characters.
This commit slightly tweak the algorithm to take space into account, but
to make sure they are not used to compound the score for a string. This
means that space characters are not ignored, but are not really
as important as a normal character.