wrong sql conversion, not_equal should be converted to <> (instead !=)

[chstorb]

Merge request checklist

• I read the guidelines for contributing
• I created my branch from dev and I am issuing the PR to dev
• Unit tests are OK
• If it's a new feature, I added the necessary unit tests
• If it's a new language, I filled the __locale and __author fields

[mistic100]

Why bothering since both are supported by every DBMS ?

And you can configure it at runtime :

$('#builder').queryBuilder({
  sqlOperators: {
    not_equal: { op: '<> ?' }
  }
});

[chstorb]

When creating comparison expressions in .NET Framework, the operator != (not ISO standard) isn't allowed.

[mistic100]

If I change it I am 100% sure someone will come asking for help because it's system only works with "!=".

I do not say the change is not legitimate, but since you have a simple solution to use "<>" where you need I prefer to not take the risk to break things.

[chstorb]

I recommend <> to use because it is ANSI SQL-92 compliant.