Removing the automatic new() implementation from the node derive macro.

[ostrosco]

For a more consistent experience, #[derive(Node)] no longer implements new() automatically. This puts the onus on the node author, but this allows for documentation of new() and significantly more flexibility in node constructors.

• Implemented new() for each node. Many functions that were helper functions for creating nodes have been moved into the new() functions for the nodes.
• Updated all of the unit tests and documentation.

[garbagetrash]

Looks good to me, really liking the new new syntax for everything, way cleaner.