Introduced browserify

0. Renaming
   * script.ls -> main.ls
1. Added two more package to the project
   * run-sequence
   * vinyl-source-stream
2. Added require() statement at the beginning of main.ls
3. Rewrote Gulpfile.js: building process changed
   i.   Copy all 'src/*' to 'build/*'
   ii.  Compile livescript into javascript
   iii. Browserify (js concat)

Great!
Enabled js minify (uglify)