googledrive: File Picker now only selects a folder
googledrive: File Picker now only selects a folder

Before this change, user would choose multiple individual text files, from any folder.

Now she can only pick a single folder. This the first step for a change in
behavior, so MoneyLog can load all text files inside that folder. Also, a
possible config.js file can be supported.

aureliojargas/moneylog,aureliojargas/moneylog,aureliojargas/moneylog,aureliojargas/moneylog