pagevideos: Prevent renaming video if file name prefix is already used
This prevents some issues and weirdnesses with losing the video thumbnail, etc.
[package]
name = "land2d"
version = "0.1.0"
authors = ["Andrey Korotaev <a.korotaev@hedgewars.org>"]
edition = "2018"
[dependencies]
vec2d = { path = "../vec2d" }
integral-geometry = { path = "../integral-geometry" }