various refactor opportunities src/app.js

[jspaaks]

Here's a couple of ideas for making the code easier to read.

• CSVSeparator, CSVHeaders, CSVQuote, CSVComment are properties of app while they only get used lower in the hierarchy
• fullscreenMode, mobileBrowser and demoSession are booleans therefore they should be named isFullscreen, isMobileBrowser and isDemoSession
• local functions such as these should be at the top of the outer function because of function hoisting
• the load/save session interactions as well as the functionality related to the welcome message could be loaded from their own modules.
• (part of) widgetFactory and viewFactory should be moved to a place lower in the hierarchy. AFAICT they generate widgets in related to the Analyze view only, so that's where they need to be then.