fix: update plupload to v2.1.1 & UI/Plupload play well with Twitter Bootstrap

rename web/MultipleFileUpload => public/

commits: #473c4dc5bd2190e487c9b661c96a64664c305a54 & #816884dde8cb657a317746081d52b199d561ee84
webalize control ID (removes '\' namespace separator)
add support for nested Nette\Forms\Container in HTML4SingleUpload Controller
public MFU refactoring, common setup for ajax&non-ajax submission

`useAjaxSubmit` variable replaced by implicit nette.ajax.js handler
added support for novalidate submit buttons, e.g. 'Cancel'
remove redundant monitoring (already in UploadControl)