URLs with special characters/umlauts raise error (alpha 3)

[aszakacs]

Describe the bug Adding a server with an umlaut, e.g. "ö", raises a FormatException. The "ö" character is converted to %C3%B6.

To Reproduce Steps to reproduce the behavior:

1. Go to "add source"
2. try adding a server with URL containing "ö"
3. enter username and password
4. See error

Screenshots