Add newlines after generated <#Include> statements
Do not generate tons of useless entities by default

They can be restored by passing a magic value as entities list.
However, we probably should simply get rid of this completely.
Add new magic function GenerateDocumentation
Add three demo invocations of GenerateDocumentation
CreateMainPage: allow specifying extra XML includes

This is done via PackageInfo.g.
PackageInfo.g: Add AutoDoc rec

Specify a custom Copyright and extra includes for CreateMainPage.
Add regenerated title.xml and AutoDoc.xml files

This in particular demonstrates how to use the new function for
packages that do not themselves use AutoDoc.
HACK: why VERSION?
Create output dir if it is missing
Invoke scaffolding code directly

This way, we have more control over it. E.g. we could now pass
extra optional arguments to CreateTitlePage or CreateMainPage.

Moreover, we are now one step closer to using GenerateDocumentation
without using any of the primary AutoDoc features (the scaffolding
code is mostly independent from the rest of the AutoDoc code).
Remove scaffolding code from CreateAutomaticDocumentation

There is no real benefit from allowing that here, interested parties
can simply invoke CreateTitlePage and/or CreateMainPage directly. (With
one caveat: Those functions rely on
  AUTOMATIC_DOCUMENTATION.path_to_xmlfiles
being set. Temporary workaround: Invoke CreateAutomaticDocumentation
first or set the variable yourself.

Bonus effect: The long argument list of CreateAutomaticDocumentation
get shortened by two arguments (of which `entities' even was
undocumented).