0.4.0 breaks node v0.8 and v0.6 compatibility

[mandric]

npm install fails, see:

https://travis-ci.org/kanso/kanso/jobs/38924958
https://travis-ci.org/kanso/kanso/jobs/38924961

I added v0.6, v0.8 and v0.10 to the travis config file a while back. Does kanso want to continue supporting these?

$ node --version
v0.8.28
0.36s$ npm --version
1.2.30
0.01s$ nvm --version
0.17.1
4.72s$ npm install 
npm http GET https://registry.npmjs.org/progress
npm http 200 https://registry.npmjs.org/progress
npm ERR! Error: No compatible version found: progress@'^1.1.8'
npm ERR! Valid install targets:
npm ERR! ["0.0.1","0.0.2","0.0.3","0.0.4","0.0.5","0.1.0","1.0.0","1.0.1","1.1.0","1.1.2","1.1.3","1.1.4","1.1.5","1.1.6","1.1.7","1.1.8"]
npm ERR!     at installTargetsError (/home/travis/.nvm/v0.8.28/lib/node_modules/npm/lib/cache.js:719:10)
npm ERR!     at /home/travis/.nvm/v0.8.28/lib/node_modules/npm/lib/cache.js:641:10
npm ERR!     at saved (/home/travis/.nvm/v0.8.28/lib/node_modules/npm/node_modules/npm-registry-client/lib/get.js:138:7)
npm ERR!     at Object.oncomplete (fs.js:302:15)
npm ERR! If you need help, you may report this log at:
npm ERR!     <http://github.com/isaacs/npm/issues>
npm ERR! or email it to:
npm ERR!     <npm-@googlegroups.com>
npm ERR! System Linux 2.6.32-042stab090.5
npm ERR! command "/home/travis/.nvm/v0.8.28/bin/node" "/home/travis/.nvm/v0.8.28/bin/npm" "install"
npm ERR! cwd /home/travis/build/kanso/kanso
npm ERR! node -v v0.8.28
npm ERR! npm -v 1.2.30
npm ERR! 
npm ERR! Additional logging details can be found in:
npm ERR!     /home/travis/build/kanso/kanso/npm-debug.log
npm ERR! not ok code 0