Initial code checkin

Very rough initial version that has necessary C# API bindings for
official GOG.com API, support API authorization flow. This would be
used for local files verification.

Additionally the app can download local data cache - dataCache.json
(and .js for easier browser consumption) and game product images. There
is initial html that can consume this and show on a single page,
supporting high-resolution assets on high DPI displays. There would be
detailed view as well as search, etc.
prepare for getting user data from site
Fixing typos to make this compile after refactor
End to end site data update - available games, images, user games
img srcset shim for browsers that don'r support it
Make owned games List<int>; check if we have enough auth data to proceed with authorization; save .json, not only .js to load existing data before we download all available data
Download games from account to track owned but no longer available games. Use account shelf cover image for those (doesn't look great, but better than nothing). Also navigate section quickly now
Add keywords from account shelf to game titles for rudimentary search. Hope to improve it soon to search by individual words with AND combination
Search in html now uses individual words with AND

Works great on keywords from account (try “osx bullfrog”)
Fix search being case sensitive
Fix img srcset shim not working on Windows IE for cover images
Slightly changed OwnedNotAvailable title to be less dramatic
Few css fixes
Few more minor css tweaks
Even more css fixes to layout
Don't break on first existing product

but rather on first page with all existing products
Actually stopping update when first full existing page was encountered. Last round of css fixes
Break on products page that has no new items. Sort products before saving by release date
Actually saving results in the right order
Code refactoring to separate SiteImages (more coming); Wishlisted games are now listed separately