Imagepanel improvements

[pnichols04]

Improvements to ImagePanel
181f174

• Previously, ImagePanel requested every image in its model from
  ImageManager. Now it requests only those images that are actually
  inside the viewport. This improves rendering time in proportion with
  the number of items outside the viewport; improvements are substantial
  with more than a few dozen off-screen items, such as for large asset
  folders.

• Previously, a call to setGridSize(n), where n was the existing value
  of getGridSize(), would raise a PaintEvent, even though the visible
  surface of the Component had not changed. This has been modified
  so that a PaintEvent will only be raised if the new property is
  unequal to the existing value. Similar changes are made to
  SetSelecionMode(...), SetShowCaptions(...), setShowBorders(...)
  and setModel(...).

• Spacing was increased, particularly around captions. Previously,
  captions ran very close to each other and to any image below them,
  creating a cluttered appearance.

• Images are now rendered with bilinear interpolation when they are
  being scaled down and bicubic interpolation when they are being scaled
  up, to eliminate the artifacts and muddiness associated with the nearest-neighbor
  interpolation used previously. No interpolation is applied if the image
  is rendered at its natural size.

• Text is now rendered with antialiasing, using the label font specified
  by the theme.

• Mouse event bounds now include the caption, so that captions will
  trigger tooltips and click handlers, consistent with similar controls
  (such as file browsers) on all three target platforms.

• Truncated item names are now determined heuristically. Previously,
  truncation used an iterative brute-force approach that allocated a
  number of strings on the heap and then discarded them.

KNOWN ISSUES.

• Tooltips are not triggered until the Component, or
  sometimes the application, loses and regains focus. This is a
  pre-existing issue that was not reprodicible with sufficient reliability
  to diagnose and correct.

• The ImagePanel used by LookupTablePanel does not refresh its
  scrollbar visibility when the model changes (i.e., when a campaign is
  loaded). This is a side-effect of the way that LookupTablePanel
  creates its JScrollPanel, which does not preserve the Component
  hierarchy from within the scope of the ImagePanel, and as such, leaves
  no parent to be notified when the ImagePanel revalidates. This is a
  pre-existing issue.

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This change is 

[Azhrei]

Wow, this modifiers 45 source files! Um, silly question, but can we break something like this up into separate issues/PRs next time!! (I understand some things will require updates to a lot of files, such as changing params to a method in an interface, but this seems to be multiple unrelated issues.)

Thanks for the updates, though. Looking forward to trying this out.

[pnichols04]

Um, silly question, but can we break something like this up into separate issues/PRs next time!!

I think next time I'll just try to PR into the right branch, the first time, instead.

See #691, #694, #695

[Phergus]

And PRs should always reference an open issue for tracking purposes.