add functions for survival, growth, and to handle phenotype and genotype

[virgile-baudrot]

All functions work and have their test. But most of them have to be pool into more generic ones.

[rafaqz]

Looks great! I wont actually merge this into master yet, instead I'll check out your branch and rebase it and try to resolve those changes and merge it into another branch.

Some notes for future, some time before this is in master:

• Try to avoid adding package dependencies, as we will all have to load all of those all the time. Instead just use those in your scripts as much as possible. We will publish this package soon and we need to keep the dependencies as lean as possible.
• This package now mostly sticks to https://github.com/invenia/BlueStyle, so final merged code needs to be in BlueStyle - no camelCase variables :)
• 92 character maximum width as much as possible

But I will edit it and merge it into another branch that you can continue to use until we have polished it up.

[virgile-baudrot]

* Try to avoid adding package dependencies, as we will all have to load all of those all the time. Instead just use those in your scripts as much as possible. We will publish this package soon and we need to keep the dependencies as lean as possible.

ok. Well yes, I commited Manifest.toml and Project.toml. But no other packages are actually required. It's because I tested some other package within the project environment...