Make hackersonly.exclude_reference default to True, since in most cas…

…es the reference sequence isn't 'real' data, and people won't want it included in downstream.

ipyrad/core/params.py

@@ -42,7 +42,7 @@ def __init__(self):
             ("demultiplex_on_i7_tags", False),
             ("declone_PCR_duplicates", False),
             ("merge_technical_replicates", True),
-            ("exclude_reference", False),
+            ("exclude_reference", True),
             ("trim_loci_min_sites", 4),
         ])