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This properly links dylibs set during build instead of expecting
the libraries to be in the system path.

UDMF special 502 now must scale arg 2 and 3 in the same scale
space as line length scrolling in binary format. This
is to ensure compatibility with the binary format.

Fixes STJr/SRB2#862

Co-Authored-By: MascaraSnake <jonassauer27@gmail.com>

Fixes STJr/SRB2#865

Also clean up redundant "startingspheres" variable

Fixes #71

- Added A_SetShadowScale
- Added A_ShadowScream which combines the above with A_Scream, used for 
badnik explosions
- Gave flickies drop shadows