Provides a functional api to make commits. It is centered around the concept of a changeset.

A changeset is an object that accumulates a series of changes to the repository that will eventually generate a commit.

A changeset can be created by calling `from-revision` or `from-branch!`.

A changeset can be "changed" by using `put-content`, `update-content`, `delete`, etc. Those functions don't actually
change the changeset but return a new one.

`get-content` will return the content of a file correspondent to the state of the provided changeset.

Once the necessary changes have been made, `commit!` will generate a commit having the changeset base revision as its parent.

`commit!` will not update the head of the branch, but `create-branch!` and `update-branch!` can be used to do that.
That allows one to make a series of commits and only change the branch when they are ready to, which makes it easier
to make processes idempontent, since if anything wrong happens the intermediary commits can just be ignored.

Note: The internal format of the changeset is considered an implementation detail and should not be relied upon.
Always create a changeset using one of the factory functions (e.g. `from-revision`, `from-branch`).

Provides auxiliary functions to work with issues via github api.

Provides functions to work with pull requests via github api.

Provides auxiliary functions to work with repositories via github api.