Add TrackWaypoint layer Delete menu options for routes.
[DOC] Fix internal document linking when used with Yelp.

Need to use xref instead of link to cross reference between high level sections.
Section ids then need an xreflabel to ensure each of the xml processing (yelp, to html + to PDF) generate the same text.
[DOC] Improve Acquire help wording and links to TrackWaypoint layer.
[DOC] Promote individual layers into top level sections.

Most layers now have more detailed help they deserve to be separate sections.
Add xref links to the layers.
Also some minor edits.
[DOC] Add further TrackWaypoint detail.

+ sublayer options.
+ delete options.
+ finish track/route options
+ visit webpage.
+ Create Route tool.