Add CDMF Charlson

[kenkomodo]

• Added comorbidity category codes from Glasheen et al. (2019)
  • Full list of ICD-9-CM and ICD-10-CM codes for each category available in paper's appendix
• Added CDMF weights; ensure that weights would only be applicable if user is applying charlson_icd9_cdmf or charlson_icd10_cdmf
  • Weighting described in paper's appendix
• Added CDMF labels for the extra categories specific to CDMF Charlson
  • Left labels the same as other Charlson algorithms where categories overlapped
• Added CDMF Charlson-specific hierarchy to .assign0() function
  • Hierarchy described in paper's appendix
• Updated comorbidity() function accordingly
  • Added code to ensure that aids is only left as 1 if individual also has an hiv code, regardless of assign0 argument (based on implementation in Glasheen paper)
• Updated function documentation and changelog to reflect CDMF Charlson option; updated sysdata.rda accordingly

Closes #79