Support Not Operator

[ssteiner]

Hi

I've already implemented this in an older build of the main sqlite-net, but I'm sure it would help some others, so here goes (I'm sorry I'm not really a git user so I've never done a pull request)

In TableQuery.cs, method private CompileResult CompileExpr(Expression expr, List queryArgs), before else if (expr.NodeType == ExpressionType.MemberAccess) you add another else if containing the following code

else if (expr.NodeType == ExpressionType.Not) {

            var n = (UnaryExpression)expr;
            var ty = n.Type;
            var valn = CompileExpr(n.Operand, queryArgs);
            switch (n.Operand.NodeType)
            {
                case ExpressionType.MemberAccess:
                    valn.CommandText += " = 0";
                    break;
                case ExpressionType.Call:
                    valn.CommandText = valn.CommandText.Replace(" like ", " not like ");
                    valn.CommandText = valn.CommandText.Replace(" in ", " not in ");
                    valn.CommandText = valn.CommandText.Replace(" = ", " <> ");
                    break;
                default:
                    break;
            }
            return new CompileResult { CommandText = valn.CommandText };
}

Do that and you get your standard NOT operator support working for booleans, strings, collections and values you can compare with = and <>.

Rather than having to keep my own copy of the lib, I think it would be easier to just mainline it.