making sure that questions are saved on the server
getting the numeric question working

- clearing left panes on answer switching
- destroying the models on answer type change if saved
create dup models so that values persist across answer type switches
Merge https://github.com/MavenHive/ashoka-survey-web

Conflicts:
	app/assets/javascripts/backbone/survey_builder_v2/views/answer_type_switcher.js.coffee
merging in all the other answer types by @s2bshakti