wscript: drop unused "mandatory variables" 'top' and 'out' in libs

Variables by these names are only used from the local wscript and when
running "waf configure", which already for other reasons only can run at
the top-level.

These variables are thus not mandatory and not used.

libs/audiographer/wscript

@@ -13,10 +13,6 @@ AUDIOGRAPHER_VERSION = '0.0.0'
 #   0.0.0 = 0,0,0
 AUDIOGRAPHER_LIB_VERSION = '0.0.0'
 
-# Mandatory variables
-top = '.'
-out = 'build'
-
 def options(opt):
     autowaf.set_options(opt)