Can't join java servers and clicking the change skin crashes the application #125

Describe the bug
When you try to join a java server, the application crashes, same with clicking the "Change Skin" button (it was working before but now crashes).

To Reproduce
Steps to reproduce the behavior:

1. Join a server or click the change skin button
2. Bye bye application

Expected behavior
To connect to the server/open change skin menu without crash.

Desktop (please complete the following information):

• OS: Windows
• Platform: x64
• GPU: GTX 970
• Build number: 1.0.0-31ca7c9