What changed in EDuke32, build by build

Similarly to how -5 and -7 and are accepted since r3859.

Previously, the C function clipmove() returned negative values when hit a wall (32768+wallnum) or sprite (49152+spritenum) because internally, these values were encoded into a *signed* 16-bit integer. This made no difference to C code using it, since it always proceeded by bit checks, but was inconsistent with documentation on CON 'clipmove' on the wiki. The following commands are affected too, since they use the value returned by clipmove(): 'clipmovenoslide', 'movesprite'. Also, the value of actor[].movflag ('htmovflag' from CON). Also, fix 'clipmove*' in LunaCON and add lunatic/test/checknearwall.con as an example of how to implement a being-close-to-a-wall checker as requested in http://forums.duke4.net/topic/7869-determining-closeness-to-a-wall/

This is exactly the same as the actor[].movflags member in the Lunatic build: http://lunatic.eduke32.com/lunatic.html#actor

This means that the internal change done to these sprite members in r3159 is hidden from CON for backward-compatibility purposes. Note that .cstat and .{ceiling,floor}stat aren't touched, and will return unsigned values to CON.