Unit Tests

[efletcherPIFSC]

Add unit tests (usethis::use_testthat) to ageproR for

• Creating a new agepro_model
• Creating a new agepro_inp_model
• Creating a new agepro_json_model
• Set Single and Mulit Recruitment models
• Set Bootstrap to package's example bootstrap file
• Importing package example *.INP to agepro_inp_model
• Check process errors "by weight" references a valid process error by wieght
• Check if agepro_inp_model fields copied over to agepro_json_model and not referencing other classes