WiFi transfer plugin and standalone app (does not require Total Commander)

A pre-release version of this plugin is available now in the store. Details here:
http://ghisler.ch/board/viewtopic.php?t=43760

Important note: This app does NOT contain any ads. However, it contains a link to Total Commander in the upper right corner if you use a Web Browser to access the files, and this plugin as the server. This is treated as an ad by the Play Store.

This plugin/tool supports direct connections via HTTP over WiFi/WLAN between two Android devices, or between Android (Server) and any device or computer with a Web browser or WebDAV client.

It creates a local Web+WebDAV server. The server URL can either be scanned as a QR-Code, or entered manually.

Although this is mainly a plugin for Total Commander, it can also be used standalone: Simply select some files in any file manager, or text, or an URL, and then use the "share" function to send it to the WiFi plugin. This will start a server and show the URL and QR-Code for the server.

Great to transfer data locally between two Android devices without going through the cloud! Your data will never leave your own wireless LAN network.

Note: Both devices need to be in the same WiFi network. If the sender isn't part of a WiFi network, this tool will offer to create its own access point, or start a WiFi direct connection. Other devices can then connect to this network to transfer data. If you scan the QR-Code from a copy of the WiFi plugin, the connection will be established automatically, and closed automatically when disconnecting.

3.4:
- option to use fixed path /8888 with user name/password (DIGEST authentication)
- support WiFi direct server on Android 10, requires LOCATION permission (only requested when needed)
- preserve timestamp on upload (to internal memory on Android 9 and 10 only)
- configurable port number
3.3:
- show notification during active connections to keep connection alive
- web client: allow to download zip with utf-8 names
- fixes to handle power saving functions