#883 Wastes memory when project over 100 years long

[Polymorpheus]

GanttProject needs 142,508 kB stack space to render my project, which has only 27 tasks and 7 resources but spans the period from 1993-01-01 to 2144-09-11 (it's a technology tree to help develop the setting for a science-fiction novel). I had to edit the JNLP file to have the JVM provide this much memory.