Rename DARGON_UTILITIES_DIR constant to DARGON_DEVELOPER_SCRIPTS_DIR.
Hub Fork call does not create "$USERNAME" branch.

Instead, we create "upstream" pointing to the-dargon-project and origin
pointing to the developer's fork.

Pair: ItzWarty.
dargonPull -> dargonPullOrigin and dargonPullUpstream.

Pair: ItzWarty.
Check for .git directory over its repository directory.

We were deleting the contents of the repository directory rather than
the repository itself. This fixes that use case.

Pair: ItzWarty.