Fix incorrect coercion to string method

D/encoding worked differently and more loosely in py2. Now decoding converts bytes to unicode, vice versa for encoding. Also, fix a duplicate conditional expression that captures strings to capture integers too.

Author: fungjj92

opentreemap/exporter/util.py

@@ -4,11 +4,11 @@
 def sanitize_unicode_value(value):
     # make sure every text value is of type 'str', coercing unicode
     if isinstance(value, str):
-        return value.encode("utf-8")
-    elif isinstance(value, str):
         return value
+    elif isinstance(value, int):
+        return str(value)
     else:
-        return str(value).encode("utf-8")
+        return value.decode("utf-8")
 
 
 # originally copied from, but now divergent from: