Alternative location for document buffers

[nokome]

Currently, when you install the desktop app, some user guide Documents are installed on the system. Right now they are stored to the user's "Documents" folder e.g. ~/Documents on Linux. It may be better to put these (an other document buffers) in places specifically meant for app data e.g. AppData on Mac, ~/.local on Linux. And wherever they are put, they should get removed on uninstall see #13 .