Equalized PRNG number distribution - Part 2
Input validation

You shouldn't just change the user input if it is wrong. If a user calls var random_number = new RNG( 10, 19.9 ); they will expect to get number between 10 and 19.9. But that's not what they will get, because their assumption is wrong (your random number generator only generates integers). A user should be informed about this, instead of just silently correcting their wrong assumption.

Regarding I've completely ignored it to keep my code a little DRY and to improve performance: Are you sure that there is a performance problem? Because it doesn't seem like it (instantiating a new RNG is something that probably isn't done all that often), and the code is quite hard to read because it does too many things (changing data and comparing data), and it uses tricks (shifting instead of casting), which is generally not recommended, as it hurts readability.

Array Generation

This:

                for( var i = 0; i &lt;= max - min; i++ )
                {
                    avail[i] = min + i;
                }


Would be a more natural and easier to read written as this (you can immediately see if min and max are inclusive or not:

                for( var i = min; i &lt;= max; i++ )
                {
                    avail[i] = i;
                }


Comments

It's good that you added comments (although using a bit less tricky code would probably reduce the need for some comments in the first place).

But this comment is a bit misleading: //returns a random element between 0 and avail.length (excluded): The next line also changes the array, something the comment doesn't mention at all. I would rewrite it as removes and returns random array element (you don't need the range, as its from the complete array, which makes sense).