The only major issue with the console based progress solution is that
the user would have to remember to press "Toggle System Console" before
the export. This button corresponds to the operator
`bpy.ops.wm.console_toggle`. Unfortunately, Blender does not expose a
way for us to query the console state. So, we have to get nasty and use
ctypes to ask the OS if the console window is active. The user may
already have it open and hidden behind Blender's UI, after all.
This changeset causes the console to open during the export (unless
disabled in the export operator). If the console was closed before the
export, it closes again once the export is finished, unless there is an
error. If the console was open, it remains open.
Unfortunately, this only works on Windows. But, according to the source
code of `bpy.ops.wm.console_toggle`, Blender's `ghost_toggleConsole`
only functions on the Win32 subsystem... SDL, X11, and Cocoa are all
no-ops. Future work would include a patch submitted to Blender adding an
enum property to the console operator to avoid this code duplication.