Update Datetime.java

Improved Javadoc, this time without derping!
Refactored RandomAccessList

RandomAccessList<T> is now an interface, extending List<T>. The old
RandomAccessList<T> is now RandomAccessArrayList<T>.
New magic formatting

Formatter can now get the ID/name of the thread that logged the message
Update ExtProperties.java

Improved Javadoc, plus a method for getting a sorted array of property
keys
Create WebUtil

Abstract web utilities, currently only a method to download a possibly
binary file
Create Wheel

It's basically a list that can wrap its content