Use g and h to go back and forth in slides

I'm using [RemoteDroid](http://remotedroid.net/) to use my phone as a remote (the advantage being that the server works on any platform, including Linux) over wifi.

However, RemoteDroid does not have arrow keys, but you can access a virtual keyboard, which lets you use letter keys, so I'm mapping `g` and `h` to prev and next.

This might be useful to other people using this kind of remote control apps.