Prefixes can be in the 1<<15 space, not 1<<8 space.
Rendering journal book text (usually Unicode) did not check to see if the font
actually had characters present for a text character under consideration while rendering.
Put in checks that will fall back on a wctob() mapped character if available,
otherwise render a space (L' ') character.
This fixes various date formatting problems when building on a system where time_t is 64-bit (e.g. Visual Studio 2010), and, as a bonus, extends the range past 2038 on such systems.
The wire protocol is left at 32-bit for now, we might change that to 64 when other reasons to break compatibility have accumulated.