rolled back the other changes and retained only the nuget configuration.
Merge pull request #424 from phreed/master

Added the nuget configuration.
Generated documentation
Updated man page for zchunk
Generated documentation
Added zlog system logging facility

- on UNIX/LINUX, uses syslog
- on other systems, does an fprintf() to stderr, for now
Merge pull request #426 from hintjens/master

Added zlog syslog class, and other smaller fixes