add divisible column to get_balances API calls

- makes determining asset divisibility possible without additional API calls
- solves issue #1199

counterpartylib/lib/api.py

@@ -279,6 +279,9 @@ def value_to_marker(value):
 
     query_result = db_query(db, statement, tuple(bindings))
 
+    if table == 'balances':
+        return adjust_get_balances_results(query_result)
+
     if table == 'destructions':
         return adjust_get_destructions_results(query_result)
 
@@ -292,6 +295,19 @@ def value_to_marker(value):
 
     return query_result
 
+def adjust_get_balances_results(query_result):
+    filtered_results = []
+    assets = {}
+    for balances_row in list(query_result):
+        asset = balances_row['asset']
+        if not asset in assets:
+            assets[asset] = util.is_divisible(db, asset)
+
+        balances_row['divisible'] = assets[asset]
+        filtered_results.append(balances_row)
+
+    return filtered_results
+
 def adjust_get_destructions_results(query_result):
     filtered_results = []
     for destruction_row in list(query_result):