Refactor __main__ logic

Most of this is just de-pyramiding the code, removing else clauses that
are unneeded (or making the if such that the else is not needed).
Rationale is simple, every level of indentation adds more that the
reader needs to keep track of.

collate.py

@@ -185,20 +185,24 @@ def addships(data):
 if __name__ == "__main__":
     if len(sys.argv) <= 1:
         print('Usage: collate.py [dump.json]')
-    else:
+        sys.exit()
+
     # read from dumped json file(s)
     session = companion.Session()
-        for f in sys.argv[1:]:
+    for file_name in sys.argv[1:]:
-            with open(f) as h:
+        data = None
-                print(f)
+        with open(file_name) as f:
-                data = json.load(h)
+            print(file_name)
+            data = json.load(f)
+
         if not data['commander'].get('docked'):
             print('Not docked!')
+            continue
 
         elif not data.get('lastStarport'):
             print('No starport!')
+            continue
 
-                else:
         if data['lastStarport'].get('commodities'):
             addcommodities(data)