doc.biohtml: add links to figures
doc.biohtml: implement “foldable included modules”
doc.biohtml: overload html_of_module_type_kind
doc.biohtml: display modules inline
doc.biohtml: generate less files
doc.biohtml: put class definitions also inline
doc.biohtml: do some code/build clean-up
doc: add figures for the Transform API
doc: improve documentation of the Bam module
doc: change headers levels in intro.txt
doc: improve CSS