Requiring jekyll-import gem. Printing error and exiting if it does not exist.
Remove Jekyll::Commands::Migrate
The jekyll-import gem provides Jekyll::Commands::Import, not Jekyll::Commands::Migrate.
Eliminating migrator dependencies.
Eliminating migrator tests (in this repo).
Using abort instead of puts & exit when jekyll-import gem isn't available.
Merge pull request #793 from mojombo/remove-migrators

Remove migrators - move to jekyll-import gem.
Updated history to reflect merge of #793. Closes #787.