Added BZ#986173 - Topics when chunked are too small. The builder will now attempt to work out a value for the publican "chunk_section_depth" option, instead of always using the publican default (which in most cases is too large).
Moved docbook classes that were only used during building, from the content spec commons library to the builder library.
Added an initial implementation for BZ#1030099 - Reduce noise with small topics.
Updated the implementation for BZ#1030099 - Reduce noise with small topics, to fix an issue when working with Articles.
More work on BZ#1030099 - Reduce noise with small topics.