check for NaN on score

[karpet]

This fixes an Argument exception

ArgumentError: comparison of Array with Array failed
~/.rvm/gems/ruby-2.4.2/gems/fuzzy_tools-1.0.0/lib/fuzzy_tools/index.rb:25:in `sort_by'
~/.rvm/gems/ruby-2.4.2/gems/fuzzy_tools-1.0.0/lib/fuzzy_tools/index.rb:25:in `all_with_scores'
~/.rvm/gems/ruby-2.4.2/gems/fuzzy_tools-1.0.0/lib/fuzzy_tools/core_ext/enumerable.rb:16:in `fuzzy_find_all_with_scores'

[brianhempel]

I did a once-over this code again (wow, people are using this library? Woo!) and I can't see where that NaN could be coming from.

Are you using a custom weight function? Do you have an example of a case that fails?

[karpet]

No custom code. I was able to reproduce it with this code:

2.4.2 :001 > require 'fuzzy_tools'
 => true
2.4.2 :002 > str = 'Ward 2'
 => "Ward 2"
2.4.2 :003 > pool = ['Township 1 Precinct 2', 'Township 2']
 => ["Township 1 Precinct 2", "Township 2"]
2.4.2 :004 > pool.fuzzy_find_all_with_scores(str)
query="Ward 2"
unsorted:[["Township 1 Precinct 2", 0.0], ["Township 2", NaN]]
ArgumentError: comparison of Array with Array failed
	from /Users/karpet/.rvm/gems/ruby-2.4.2/gems/fuzzy_tools-1.0.0/lib/fuzzy_tools/index.rb:26:in `sort_by'
	from /Users/karpet/.rvm/gems/ruby-2.4.2/gems/fuzzy_tools-1.0.0/lib/fuzzy_tools/index.rb:26:in `all_with_scores'
	from /Users/karpet/.rvm/gems/ruby-2.4.2/gems/fuzzy_tools-1.0.0/lib/fuzzy_tools/core_ext/enumerable.rb:16:in `fuzzy_find_all_with_scores'
	from (irb):4
	from /Users/karpet/.rvm/rubies/ruby-2.4.2/bin/irb:11:in `<main>'