Consider handling old SGF with lowercase "long properties" #68
Description
Very old SGF files sometimes have lowercase letters in the property names which should be discarded, e.g. one might see:
(;GaMe[1]SiZe[9]PlayerBlack[Miyamoto Naoki]PlayerWhite[Go Seigen]DaTe[1968]REsult[B+4];Black[de];White[fe])
By discarding all the lowercase letters in the property names we can get the Right Thing.
For some real world examples see:
Currently Sabaki doesn't handle these.