Dependency issue

[illogicalextend]

Could you consider adding a note to the README that ruby-dev is a dependency to get this working? Spent some time troubleshooting it after doing a 'gem install btce' until I finally found the answer. The error I was getting prior to having [ruby-dev ruby1.9.1-dev] installed was:

ERROR:  Error installing btce:
eRROR: Failed to build gem native extension.

    /usr/bin/ruby1.9.1 extconf.rb
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- mkmf (LoadError)
   from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
   from extconf.rb:13:in <main>