remove matrix_start and matrix_end from species model as redundant, closes #93
remove matrix_start and matrix_end from species model as redundant, closes #93

Spandex-at-Exeter/demography_database,Spandex-at-Exeter/demography_database,Spandex-at-Exeter/demography_database,Spandex-at-Exeter/demography_database,Spandex-at-Exeter/demography_database