[TIDY] Refactor renderlib into two parts

Most of the make scripts only need the schedule part of the renderlib.
The schedule part has way less dependencies (e.g. no ImageMagick), so
those scripts can be used without them now.

make-adobe-after-effects.py

@@ -2,7 +2,7 @@
 # vim: tabstop=4 shiftwidth=4 expandtab
 
 import subprocess
-import renderlib
+import schedulelib
 import argparse
 import tempfile
 import shlex
@@ -139,7 +139,7 @@ elif args.bgloop:
     }]
 
 else:
-    events = list(renderlib.events(args.schedule))
+    events = list(schedulelib.events(args.schedule))
 
 
 def describe_event(event):