Write a new signal library

[tp7]

signal_expr2( 
    c1.signal_getvalue("avg"),
    c2.signal_getvalue("med"), 
    "x y + whatever"
).signal_setvalue(last)

After 16-bit support is implemented in masktools, add a new signal library based on the same common shared lib.

Each filter in this plugin should work on a two-pixel clips (y8 or yv24), containing 16bit (msb/lsb) value of some clip parameter (signal_getvalue). The last step is always signal_setvalue that creates a full-resolution clip where each pixel has the value of input 2-pixel clip to be used with mt_merge.

This would allow extremely fast runtime processing without usage of complex avisynth runtime functions.

[tp7]

We might come up with a better way on the core level in avs+.