Optional health cross for target ID

[applesapples]

Requested it in the tf.tv thread, and you said to post it here, so here it is.

Requesting optional health cross for target IDs because like health cross for player health, it's just easier for me to see it at a glance.

Thanks!

[omp]

Added. It's in the same style as the player health, with a cross and a numerical health value side-by-side.

Replace TargetID and SpectatorGUIHealth files with the _cross variants.