create a place for graphical log handlers

Currently only used in pong.love, but let's keep the bad merge that had
it broken since September from occurring again. To do that we'll be
consistent across forks on where globals are initialized.

I haven't appreciated the implications of main.lua for load order.
log.lua comes first just because it's shared by both the main app and
its 'source' editing environment. And it just so happens that source.lua
was loading after log.lua resulting in the pong.love breakage. Now let's
lean into that and enshrine that one should initialize log_render in
log.lua.

log.lua

@@ -31,4 +31,7 @@ function log_new(name, stack_frame_index)
 	log_start(name, stack_frame_index)
 end
 
+-- rendering graphical objects within sections/boxes
+log_render = {}
+
 -- vim:noexpandtab

source.lua

@@ -1,5 +1,4 @@
 source = {}
-log_render = {}
 
 Editor_state = {}