Fix for solid white window on reopening Render Preview

Fix for #241

Upon reopening, the Render Preview window would appear a solid white when the canvas was at or near desktop resolution. Switching from `setPreferredSize()` to `setSize()` in `Chunk3DView.setCanvasSize()` seems to have corrected the issue. It is unclear whether this is a dependable, permanent fix or not.

Also added a debug target for the Ant build on the `chunky` module. This allows a debugger to connect to Chunky on port 5432 (modifiable). Use is limited because without access to the bytecode produced by Ant, the debugger can only issue breakpoints on method signatures and manually pause execution. However, it may come in handy.