V1.6.1.16: refactor: use vectors for LengthHydro and BasinAreas instead of matrices

Refs #34
3 jobs for sd in 11 minutes and 53 seconds (queued for 1 second)
Status Name Job ID Coverage
  Build
passed build_patched #97821

00:00:39

 
  Tests
passed check_as_cran_patched #97823

00:01:51

passed check_not_cran_patched #97822

00:09:23