Implement setBackgroundSurvey method
   * Update underscore-js from 1.4.1 to 1.6.0 by the way
Implement layer removal(only for additionalLayersView for now)
Add left bottom GUI visiblitiy management(mollweide, share, measure tool, samp)
Implement add/remove methods of name resolver & reverse name resolver GUIs
Implement goTo method
  * Refactor NameResolver into NameResolver and NameResolverView