web.isgd() now throws an error when it cant shorten a URL

plugins/shorten.py

@@ -1,8 +1,6 @@
 # Plugin by Lukeroge
 
-from util import hook
-from urllib2 import HTTPError
-from util.web import isgd
+from util import hook, http, web
 
 
 @hook.command
@@ -10,6 +8,6 @@ def shorten(inp):
     "shorten <url> - Makes an is.gd shortlink to the url provided."
 
     try:
-        return isgd(inp)
-    except (HTTPError):
-        return "Could not shorten '%s'!" % inp
+        return web.isgd(inp)
+    except (web.ShortenError, http.HTTPError) as error:
+        return error