* Public File Sharing
This implements public file sharing (read-only) with and without passwords (#57).
It also fixes a problem with filenames including special characters like `#` not working properly (#71).
You can share a directory or a single file, by using the new share icon on the right of the directories/files, and click on it to manage an existing file share (setting a new password, or deleting the file share).
There is some other minor cleanup and other copy updates in the README.
Closes#57Fixes#71
* Hide UI elements when sharing isn't allowed
