GL_LINES rendering not showing up in higher graphics modes

[Riot]

This occurs only on my linux test machine; either it's the fact it's Linux (unlikely) or that it has outdated notebook intel graphics.

This occurs only in prettiest and compromise graphics modes, not fastest or fugly.

Recommend adding a pre-start draw test stage where we plot lines and read pixels back to confirm operation.

Marking as critical because game is unplayable without a visible cursor

[Riot]

no longer applicable with the new shader setup