#242 upstream for VST vim plugin is dead, fix URL

[Matej Cepl]

http://skawina.eu.org/mikolaj/ is gone, so we should replace mentions of it at least with http://www.vim.org/scripts/script.php?script_id=1334 (which holds old copies of the plugin).

[Wes Turner]

A link to https://github.com/Rykka/riv.vim could also be useful?

[Wes Turner]

(a copy of) VST is hosted at: https://github.com/vim-scripts/VST

[engelbert gruber]

thanks