Add GitHub Wiki

You currently have the markdown wiki files in the wiki branch. I would like to suggest adding these as wiki pages in the GH interface.

Here's how ([credit here](http://stackoverflow.com/a/41423798/552067)):
1. Go to [this repo's settings](https://github.com/curran/google-diff-match-patch/settings) and check the "Wikis" checkbox
2. Go to [this repo's wiki page](https://github.com/curran/google-diff-match-patch/wiki), click the "Create the first page" button, then scroll down and click "Save Page".
3. Navigate to your local clone of this repo in your terminal and add the wiki page as a remote:

```sh
git remote add gh-wiki https://github.com/curran/google-diff-match-patch.wiki.git
```
4. Force push the files from your "wiki" branch to the new "gh-wiki" remote:

```sh
git push -f gh-wiki wiki:master
```