Relicence under the Vim licence, add legal info and update file headers

README.md

@@ -1,9 +1,21 @@
-# Org-mode syntax highlighting for Vim
+# Org mode and Outline mode syntax highlighting for Vim
 
-Org.vim is a minimal [Org-mode](https://orgmode.org/) plugin for
+Org.vim is a minimal [Org mode](https://orgmode.org/) plugin for
 [Vim](https://www.vim.org/). It provides only the absolute necessities (e.g.
 syntax highlighting and folding) at a high standard.
 
 The main goal of this plugin is to replicate [Vim's default
 Markdown](https://github.com/tpope/vim-markdown/) editing experience for
-Org-mode files.
+Org mode files.
+
+## Licence
+
+Copyright (c) 2018-2019, Alex Vear.
+
+Org.vim is distributed under the same terms as Vim itself.
+
+A copy of the full licence text should have been provided with this extension
+in the `LICENCE` file. The license can also be viewed on the [web][] or by
+invoking `:help license` from within Vim.
+
+[web]: <http://vimdoc.sourceforge.net/htmldoc/uganda.html#license>