[Bug] Logic in WOQLQuery().loadVocabulary
I have some doubt in `WOQLQuery.prototype.loadVocabulary = function(client)` as I test the logic:
```
var result = {}
var v="fg: hello"
var spl = v.split(":");
    if(spl.length == 2 && spl[0] != "_"){
    result[spl[1]] = v;
    }
console.log(result)
```
I got
```
{
hello:"fg: hello"
}
```
Need to fix in WOQLpy accordingly
diff --git a/woqlclient/woql.py b/woqlclient/woql.py
index 86581f6..d866d04 100644
--- a/woqlclient/woql.py
+++ b/woqlclient/woql.py
@@ -764,7 +764,7 @@ class WOQLQuery:
                     if type(value) == str:
                         val_spl = value.split(":")
                         if len(val_spl)==2 and val_spl[1] and val_spl[0]!='_':
-                            self.vocab[val_spl[1]] = value
+                            self.vocab[val_spl[0]] = val_spl[1]
 
     def getLimit(self):
         return self.getPagingProperty("limit")
['woqlclient/woql.py']