escape summoner names via escapeHTML

I found a bug when searching the summoner named 'Snö Varg'. It gave me a 404 although the summoner exists.

Doing a google search, I found [this discussion](https://developer.riotgames.com/api/methods#!/506/1636) that pointed me on this [best practice page](https://developer.riotgames.com/best-practices) (read the **Summoner Name Encoding** paragraph).

It appears that summoner names should be HTML escaped, not URI escaped. `CGI.escapeHTML` seems to solve the problem.