add react-router

rebase changes from master
Merge pull request #20 from rtfeldman/react-router

React Router

see /client/app_router.js on how to add routes and route handlers
Hook up AppRouter with page level components
Merge pull request #29 from rtfeldman/link_up_components_with_router

Hook up AppRouter with page level components
update package.json
karma-cli required for npm test
fix react WARN about unique keys
SurveyEditor: Question removal + EditEssayQuestion
SurveyEditor: Finish EditYesNoQuestion
SurveyEditor: Finish EditMultipleChoiceQuestion
SurveyEditor: Style various EditQuestion types
SurveyEditor: Add tests for various question types
Merge pull request #30 from rtfeldman/edit_questions_on_survey_editor

SurveyEditor: Add edit question forms
add merge dependency
initial api implementation
Karma to only use test/client