Fix missing open-brace in config.c
Address the more trivial subset of danakj comments
Revert "Remove now-unused config_place_center option."

This reverts commit 5e282dae08be3b900e0337efa0fae8f3ffa92cd7.

Conflicts:
	openbox/config.c
	openbox/config.h
Remove reliance on sentinel value when scanning edge arrays

Avoid need to initialize Size structure by removing it :)

Clean up field expansion code somewhat

Compress code further by using a structure for common args

Fix search for next grid point