Uncapped Water Ripples

!1783 (merged) missed the water ripple effect on water FOF surfaces, making it only update once per tic instead of every frame. This merge request remedies that, for both software and OpenGL.
The OpenGL shaders weren't edited; the leveltime shader uniform was already a float, counting in seconds, so any shader add-ons should support this change.

I've made sure that with fpscap 35, each rendered tic's FOF ripples are 100% identical to before this merge request, in both software and OpenGL.

This merge request also uncaps the underwater post-processing effect in software (it was already uncapped in OpenGL), and synchronises it with the level time and timescale in OpenGL like how software handles it (instead of having it only "progress" while actively shown).

As a bonus, the heat wave post-processing effect in software is no longer sped up at >35 FPS (but still slowed down at <35, and only semi-affected by timescale). By nature of the effect scrolling one row of pixels per tic, it's hard to uncap it.
(In OpenGL, it's uncapped and synchronised with the level time and timescale, as it's just a variant of the underwater effect.)