Forgot to update the built-in menu's way of bringing up the help when I
updated the main help file tag in
8606ac8ce8e7d872da5b77e644fd32ac4c7fd26b.

This way, entering `h` in the game's main menu will correctly bring up
the plugin's help documentation.

Very minor version includes mostly documentation updates in preparation
for a public alpha release.

Include information about the v0.0.1 release, copied from the v0.0.1 tag
message.

Include some very minor background information about the plugin along
with an animated demo gif.

Also include requirements, installation, and license information.

Realised that the Vim plugins I see (and the ones I've written
previously) use the name of the help file as their main first tag,
namely using a `.txt` extension. Let's go with that convention.

List the plugin's external dependencies, currently only `mplayer` which
is used to play game audio.

To ensure that the help file opens at the top. Otherwise for some reason
it was opening at *space_vlaze-h* for me.

Otherwise the inputs get compared as strings and only the leftmost digit
of the number gets sorted so you end up with things like this:

    [8, 43, 2, 13, 0]

Convert our inputs to numbers so that they get compared in their
entirety and larger numbers move to the head of the list.

Didn't really like the last one so modified it a bit to try to make it
less harsh. Still not a huge fan but it's better than before.