Bump kramdown, rake, shoulda, cucumber, redcarpet
Add test/unit
Dont test kramdown

It should have it's own tests for that
Update history to reflect merge of #768
Merge pusewicz/bump-gems from #744
Updated history to reflect merging of #744.
Updated Kramdown tests to reflect numeral HTML entities.
Aliased jekyll server to jekyll serve
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.
Merge pull request #792 from mojombo/alias-serve-to-server

Aliased jekyll server to jekyll serve
Update history to reflect merge of #792. Closes #789.
Removed migrate tasks from Rakefile.
Remove migrator files from jekyll.gemspec

Some files no longer exists but was not removed from jekyll.gemspec:
- lib/jekyll/commands/migrate.rb 
- lib/jekyll/migrators/*.rb