Closes #31 wrapper functions for waist/hip and waist/height ratio #97

Job	Run time
Get R version	1s
Links / Validate Links	45s
Check / (release)	6m 11s
Check / (devel)	1m 15s
Check / (oldrel)	3m 5s
Documentation	0s
Validation	0s
Man Pages / Roxygen	2m 17s
Lint / Lint	2m 16s
Code Coverage / Test Coverage	3m 20s
Spelling / Spellcheck	3m 12s
Code Style / Code Style	2m 16s
Check Templates / Verify	3m 7s
Code Coverage / Generate badge for coverage	7s
	27m 52s

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