epidesc 0.1.0

• Initial release.
• Provides epiyearweek() to format dates in epiyearweek ("yyyyww") format.
• Provides the epidemiological descriptors desc_Ap(), desc_Tp(), desc_Cnf(), desc_Cmax(), desc_Cmed(), desc_Isof(), desc_p(), desc_Cwf(), desc_Cwmax(), desc_Cwmed() and desc_Inc().
• Provides desc_list() with the catalogue of available descriptors and desc_year() to compute them per spatial unit and epidemiological year.
• Includes the dengueRio example dataset.