ENH: add neocortex config to reference mask

Author: mnoergaard

petprep/data/reference_mask/config.json

@@ -15,6 +15,17 @@
     "exclude_indices": [14, 24], 
     "dilate_by_voxels": 3,
     "gm_prob_threshold": 0.2
+    },
+    "neocortex":
+    {
+    "refmask_indices": [
+    1001, 1002, 1003, 1005, 1006, 1007, 1008, 1009, 1010, 1011,
+    1012, 1013, 1014, 1015, 1016, 1017, 1018, 1019, 1020, 1021,
+    1022, 1023, 1024, 1025, 1026, 1027, 1028, 1029, 1030, 1031,
+    1032, 1033, 1034, 1035, 2001, 2002, 2003, 2005, 2006, 2007,
+    2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017,
+    2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025, 2026, 2027,
+    2028, 2029, 2030, 2031, 2032, 2033, 2034, 2035]
     }
   },
   "wm": {