Bug in auto choices mode

[Krzysztof Mirzyński]

Hi, 

I found bug in auto choices mode. 

Problem occurs when auto choices mode is active. For example for this data in one column:

- "xy1"

- "xy2"

- "ab1"

When we write in filter "xy*", we receive 2 correct values in table ("xy1", "xy2"), but value in filter takes bad value: "xy1" (should be all time "xy*", because in the table are two different values).

Problem is in condition: ret.exact = (match.str.length() == ret.len) && (len == 0 || ret.len > 0);

For data from example:

len = choice.str.length() = 3 ("xy*") 

match.str.length() = 3 ("xy1") 

and then ret.exact is true, but value in filter dosn't match fully choice value. 

I made pull request with fix. Please check it.