Refs feedback:

- fix requirements.txt
- change static CORS regex into configurable tuple list

paperless.conf.example

@@ -89,6 +89,11 @@ PAPERLESS_EMAIL_SECRET=""
 # as is "example.com,www.example.com", but NOT " example.com" or "example.com,"
 #PAPERLESS_ALLOWED_HOSTS="example.com,www.example.com"
 
+# If you decide to use Paperless APIs in an ajax calls, you need to add your
+# servers to the allowed hosts that can do CORS calls. By default Paperless allows 
+# calls from localhost:8080. The same rules as above how the list should look like.
+#PAPERLESS_CORS_ALLOWED_HOSTS="localhost:8080,example.com,localhost:8000"
+
 # To host paperless under a subpath url like example.com/paperless you set
 # this value to /paperless. No trailing slash!
 #