Add --version option and increment version to 2.0
Factor out and increase the cutoff in timing tests

Some were failing on rare occasion because the previous arbitrary number was
not big enough.
Add back -d to behave like -cC but reading from stdin

This really is a useful mode.  The implementation is pretty bad -- all
copy-paste into an already convoluted Command -- but it works for now.  The big
cleanup can happen later.
Add experimental -D for data stream expecting headers

Actual use suggests this will be useful, but time will tell.