Rename MemoryFixedDialog to DelayedPackDialog, don't mess with defaultCloseOperation

src/main/java/bdv/tools/HelpDialog.java

src/main/java/bdv/tools/RecordMaxProjectionDialog.java

src/main/java/bdv/tools/RecordMovieDialog.java

src/main/java/bdv/tools/VisibilityAndGroupingDialog.java

src/main/java/bdv/tools/brightness/BrightnessDialog.java

src/main/java/bdv/util/DelayedPackDialog.java