_oasis: change version to 0.3-dev
Added a stub VCF parser -- only header is parsed for now
Updated 'Biocaml_vcf' to use 'Biocaml_lines' and added a simple test
Added a very basic VCF row parser
doc: add a CSS file
doc,build: add a 'doctest' target

This `make` target build a small subset of the documentation (for
testing purposes).
Implemented 'INFO' parsing in 'Biocaml_vcf'
Added 'FILTER' parsing to 'Biocaml_vcf'
doc: add an ocamldoc plugin (with {figure _})
doc: improve the CSS
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