Fix link syntax.
Thanks, Github.
Hopefully fix all links broken by GitHub Markdown changes.
By replacing "[[…]]" syntax with "[…](…)" and using
"<code>[…](…)</code>" instead of backticks.
Add placeholder page for include-file.
Add page on remote authentication.
Describe the "grammar" statement.
Expand description of package definition from the command-line.
Move "Terminology" section up in the sidebar.
Usage-installing-updating.md -> Intalling-and-updating.md
Reorganize package definition vs package definition file.
Usage-runtime.md -> Runtime-use.md
Usage-querying.md -> Querying.md
Usage-publishing.md -> Publishing.md
Usage-creating-a-tarball.md -> Creating-a-tarball.md
Statements-environment-variable.md -> Environment-variable-statements.md
Statements-asset.md -> Asset-statements.md
Fix link in home and sidebar.
s/Package-Base/base package/g
Package-Named-vs-Unnamed.md -> Named-vs-unnamed-packages.md
Rename all the statement files.
Remove Gotchas because they're no longer there.
Document "set" statement overriding --set.
Link to named/unnamed package in the sidebar and home.
Skeletal docs on creating a tarball.
Mention the lack of an archive file.
Create a basic querying usage page.
Rename "Base-package" to "Package-Base".
Sidebar/Home link rearrangement.