Slightly rework HTML5 generator
Slightly rework HTML5 generator

Unify method and attribute handling

Affects: #22

gavv/rdoc-generator-singlepage,rbdoc/rdoc-generator-solarfish,gavv/rdoc-generator-singlepage,rbdoc/rdoc-generator-singlepage,rbdoc/rdoc-generator-solarfish,rbdoc/rdoc-generator-singlepage