replace Grunt with gulp
set up gulp server
remove Grunt build system
delete demo data
reorganize source structure
Added offline bower source for three.js
Avoid the problem that bower install takes so long
update bower.json to use offline source
add usemin in html to build project
remove example data
add build tags
Add build unities
add del module for clean
remove reversion for dist
Fix build error
move inline script to external js
add missing build option for images
tested build version
Merge pull request #6 from ChiChou/gulp

fix missing files in build