include search button icon

embed a generic search button icon.
Merge branch 'searchplugin' of https://github.com/razor-1/reveal.js
merge search plugin, adjust styles
remove unused file (closes #360)
Start migrating changes suitable for CJK ideograph.
Include responsive column support.
Modified gruntfile.js for automatic compression
Start translating the index.
Pushed the translation progress a little bit forward.