danlex 0.1.0

• Initial CRAN submission.
• Provides access to Danish acts, regulations and treaties from Retsinformation via its ELI service.
• Document retrieval by ELI identifier, accession number or the collection/year/number triple, with dlx_get_doc() and dlx_get_docs().
• Full text and provision-level structure via dlx_get_text() and dlx_get_paragraphs().
• Cross-references as an edge table via dlx_get_references().
• Recent changes via dlx_get_changes(), and corpus enumeration via dlx_list_documents().