onWindowStartGL() returns void.

Implement PpCmd interface for serializing commands for network transport.

Updated PpCmd interface too.

Use #defines for access() and stat().

just define our own.

Need <sys/types.h> -- for MinGW?

Handle -seconds and -frames correctly -- thanks to g++ -Wall for catching
improper ref to ws->...!

It contains only internal .h references -- not to system headers nor Syzygy ones.

will be part of this.  Prepare to package multiple commands together
so we can ship several in one display cycle.

though not to process any commands after command-line startup yet.

(Why does it need to complain about losing precision on a reinterpret_cast??)

Interpret threshholding correctly for "hist".
Make "thresh off" finally work again, too.  Good grief.