Merge sub docs

Merge sub documents into master document and create single web help system.

Custom Root Level

Promote the special outline levels to top and demote other levels.

Max tree level

Restrict the levels of the topic tree.

Merge topic at level

Merge topics at specified outline level to their parent topic.

Page filename rule

Rule for the filename of each HTML page.

Add-ins

Configure add-ins for customization your web help.