Improve ConfigNode load/save perf (#88)

* Rewrite PreFormatConfig to iterate through strings as little as possible.

* Improve logging, add @siimav's parallel processing bit (seems to be strictly slower even for 1m+ rows, tho)

* Patch writing, too, for a slight improvement in perf

* Fix a lingering issue with trailing braces

* Patch on startup, not after MM. Skipping keys will only happen after MM, but they're really just there for sfs loading, can't trust what's in gamedatabase enough to skip parsing there.

* Update readme and Settings

* Big improvements to save perf by not writing lines / flushing / using a puny buffer.

* missed a newline