Keeping core API dependencies to a minimum
Created by: andrewyatz
It seems we have others within the team that would like to use ensembl-io but will not because of the core dependency. This commit attempts to
- Remove any use of Utils::Exception and replace it with Carp
- Remove any use of Utils::IO work_with_file and replace it with an open
- Remove any unused/unnecessary imports (there were a lot)
Also this commit pulls up that simple_list.t is no longer a valid test because its dependencies are broken.