Fix quote function to correctly interpret NULL values (insert, update)

[FxNion]

When inserting an array of datas which have some keys not set to a value, the quote function intepret it as '' instead of NULL. And when the target field is an integer in db, the result stored is 0

[vrana]

Please provide an example of previously wrong behavior. The patch doesn't make much sense to me. If $val is null then isset($val) returns false.

[FxNion]

You are right, and i really apologize.

After some hollidays and severals tests i understood my error: I thank that i was passing a null value in parameters, but in fact it was already an empty string.

And the second error (in the patch) was to use == instead of === to compare '' to NULL and as you can guess, in php ''==NULL is true. Bad.

Sorry again.

$connection->exec(" CREATE TABLE test (id int(10), parent_test_id int(10) DEFAULT NULL, name varchar(255))");

$db = new NotORM($connection);                  
$db->debug=true;
$db->test()->insert(array( "id"=>1, "parent_test_id"=>'', "name"=>"test insert"));
//0 will be stored in the field ...

[halilim]

So there is no problem? If so, what about closing? I always feel bad about needlessly high bug / open pull request counts on open source projects :)