Implement the Arrays#copyOf family

... as introduced in Java 6.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Implement rest of the Arrays#fill family

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Implement TreeSet#descendingIterator

If need be, this functionality can be sped up by implementing a
descending iterator on the tree without copying it into an ArrayList.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Implement LinkedHashMap

This implementation is intentionally simple. If and when the need arises,
we can always implement a more performant version.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Implement LinkedHashSet

This implementation is intentionally simple. If and when the need arises,
we can always implement a more performant version.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>