SST Beta 0.4 (a.k.a Small Subtle Tweaks)

Mostly, this just fixes a few bugs that were overdue a fix. In
particular, 5135 Portal FOV changing, L4D warp testing, and some L4D1
console spam prevention didn't work properly if the plugin was
autoloaded. Now they do, and the plugin initialisation has been
reworked to preven those kinds of issues in general.

Additionally, multiplayer autojump is less janky for non-host players,
and demo directory checking is done in a more robust way.

As an added bonus, it's also now possible to change the Portal crosshair
colours, because sure why not!

Have fun!