Remove regression which breaks behaviour of PurchaseOrders, etc.

src/xero/manager.py

@@ -8,7 +8,7 @@ def __init__(self, name, credentials, unit_price_4dps=False, user_agent=None):
         from xero import __version__ as VERSION  # noqa
 
         self.credentials = credentials
-        self.name = name.capitalize()
+        self.name = name.capitalize() if name.islower() else name
         self.base_url = credentials.base_url + XERO_API_URL
         self.extra_params = {"unitdp": 4} if unit_price_4dps else {}
         self.singular = singular(name)