Added `bin/sgit`.
This directory is NOT intended to become a huge software project
right now. For now it is just a convenient place to store tools.
Please avoid overthinking, over documenting tools under bin.
Later on there will be a tool that builds links in the web site
from JSON files, perhaps forms HTML files from markdown files, etc.
However we will have to make major progress on issue #1, issue #2,
issue #3 and issue #4 before such code can be written.
In some cases tools put under bin might go away later on
if they are no longer needed.
Landon Curt Noll
aa263427e3