Add a bunch of missing files to the distribution.

Files from the debian directory, documents from the doc directory,
graphics from the docbook/wsug_graphics directory, and the echld
Makefile.nmake.

Bug: 10331
Change-Id: Iccccc58811753581b0b180053defd937aea22f95
Reviewed-on: https://code.wireshark.org/review/3283
Reviewed-by: Guy Harris <guy@alum.mit.edu>
Reviewed-on: https://code.wireshark.org/review/3320
Reviewed-by: Jeff Morriss <jeff.morriss.ws@gmail.com>