[BUGFIX] #760 refactor and fix bug on Gruntfile.js
[BUGFIX] #760 refactor and fix bug on Gruntfile.js

[DESC.]
- solve the problem `grunt` command is failed
- add the `compress: true` option to less task
- rename 'themeBuild' task to 'theme' (`grunt themeBuild` => `grunt theme`)
- refactoring on theme task logic and configuration

kyungmi/webida-client,leechwin/webida-client,changgyun-woo/webida-client,changgyun/webida-client,kyungmi/webida-client,gotchazipc/webida-client,minsung-jin/webida-client,leechwin/webida-client,minsung-jin/webida-client,kyungmi/webida-client,minsung-jin/webida-client,hyukmin-kwon/webida-client,happibum/webida-client,changgyun/webida-client,leechwin/webida-client,kyungmi/webida-client,leechwin/webida-client,webida/webida-client,happibum/webida-client,webida/webida-client,gotchazipc/webida-client,changgyun-woo/webida-client,happibum/webida-client,changgyun-woo/webida-client,gotchazipc/webida-client,hyukmin-kwon/webida-client,kyungmi/webida-client,leechwin/webida-client,gotchazipc/webida-client,minsung-jin/webida-client,leechwin/webida-client,changgyun/webida-client,gotchazipc/webida-client,changgyun-woo/webida-client,changgyun/webida-client,hyukmin-kwon/webida-client,hyukmin-kwon/webida-client,webida/webida-client,webida/webida-client,kyungmi/webida-client,changgyun/webida-client,happibum/webida-client,changgyun-woo/webida-client,changgyun/webida-client,webida/webida-client,minsung-jin/webida-client,hyukmin-kwon/webida-client,webida/webida-client,happibum/webida-client,minsung-jin/webida-client,happibum/webida-client,changgyun-woo/webida-client,hyukmin-kwon/webida-client,gotchazipc/webida-client