Problem when removing first element of the list

Hey guys, I think I've observed incorrect behavior when removing the first element from the list:

I simply create the list with the strings 0, 1, 2, 3

```
var LinkedList = require('linkedlist')
var list = new LinkedList()
for (var i = 0; i < 4; i++) list.push(i.toString());
```

Now I iterate through the list and demonstrate that removing an element that isn't first works fine
console.log("\nExpect 0, 1, 2, 3");

```
while (list.next()) {
console.log(list.current)
if (list.current === "1") list.removeCurrent();
}
```

We see the following output `0, 1, 2, 3` and expect that the list now contains the strings 0, 2, 3

If we now iterate through the list again but this time remove the first element we get something unexpected:

```
list.resetCursor();
while (list.next()) {
console.log(list.current)
if (list.current === "0") list.removeCurrent();
}
```

Here we see `0, 3` but we expected `0, 2, 3`

Start by reproducing the behavior with the LinkedList example using push, next, removeCurrent, and resetCursor. Trace removal of the first element after removing "1" and verify the list still iterates as 0, 2, 3 after the fix.

Written by the indexing model from the issue text.