Icons Screensaver: Update copyright header and version

Add myself to authors, assign copyright to Haiku, Inc.

Bump version to 1.0.1-final, update short and long description
Icons Screensaver: Style fixes only
Icons Screensaver: Grab vector icons via query, fixes #10166

Iterate through each BFS volume and find vector icon data in apps
using a BFS query. Cap off at 128 total icons, we could get more if
desired. Default install comes with ~100 at present.

Make sure we have at least 20 icons (15 display at a time) before we
start drawing icons.

Rename VectorIcon to vector_icon and treat it like the POD struct that it is.
Also add a type_code parame to vector_icon that should be set to
B_VECTOR_ICON.

Some style fixes also included, e.g. turned defines into static const int32’s.