VisualizeTiles: remove debugging statement
VisualizeTiles: make execution flow more granular
VisualizeTiles: refactor tile field creation

We now create the domain sets in one step, then populate the range
samples in a second step. This keeps the logic separated and clean.
VisualizeTiles: add option to load tile data

Instead of coloring the tiles with a random color, this option actually
loads the tile data at low resolution and displays it. Beautiful!
VisualizeTiles: tweak whitespace
VisualizeTiles: add minimum memory estimation
VisualizeTiles: quit JVM when quitting ImageJ