Hammer CLI

Hammer no longer supports ruby 2.0, there's no point of keeping the historical code in Gemfile:

./hammer/hammer-cli/Gemfile:
    4  
    5  gem 'gettext', '>= 3.1.3', '< 4.0.0'
    6: if RUBY_VERSION < '2.1.0'
    7    gem 'clamp', '< 1.1.0'
    8    gem 'fast_gettext', '< 1.2.0'