script to create structure on sumstats dirs

[jdhayhurst]

Need a script that will convert the current flat summary stats directories to how it is below:

summary_statistics
+-- gcst001-gcst002
|   +-- gcst001
|   +-- gcst002
+-- gcst003-gcst004
|   +-- gcst003
|   +-- gcst004
+-- gcst005-gcst006
|   +-- gcst005
+-- gcst...(left to preserve paths)
+-- author_pmid_gcst...(left to preserve paths)