* WIP: NanoBSP integration
* update to latest nano_bsp HEAD
* update to nano101 as posted on the DW forums
* include p_extnodes.h instead of declaring P_GetOffset()
* one comment
* update copyright information
* introduce W_LumpExistsWithName()/W_LumpLengthWithName()
* use W_LumpExistsWithName()/W_LumpLengthWithName() more thoroughly
* error out if no SECTORS lump found
* report failing map lump name, not number
* Check `oldlookdir` before disabling `centering`
When turning off mouselook/padlook, keep view centering enabled until `oldlookdir` is zero, meaning when the player's view actually appears centered.
* Move `viewangleoffset`
* Check dead state set by `P_KillMobj()`
* Smooth composite/mouse turning transitions
Blend interpolated composite input (e.g. keyboard) turning with direct mouse turning to prevent choppy transitions.
* Group inputs by composite/gamepad/mouse
* Update carry/input calculations
This also enables shorttics (lowres_turn) with fast mouse polling.
* Add mouse smoothing toggle
With mouse smoothing disabled (default), mouse movements are immediately reflected in each frame update, with the game simulation following behind. The higher the framerate, the lower the perceived input lag. With mouse smoothing enabled, mouse movements are delayed by up to one tic (~29 ms) due to interpolation. When recording older format demos with reduced turning resolution (or when using `-shorttics`), interpolation may still be preferred for smoother turning.
* Rename "mouse smoothing" to "raw mouse input"
* Skip calculations when using interpolation
* Allocate all video buffers/surfaces at native resolution.
* Fix HUD widgets flickering when resolution changes.
* Uncapped framerate in the menus.
* Fix memory leaks.
Introduce PU_VALLOC, which is freed when the resolution changes. Only for
visplanes for now.
* Accurate aspect ratio calculation.
