Make label readable on windows system.

Works properly on Win8.1 i686
Fix QSplitter handle color on Windows
Fix header spacing in widget.ui
Improve file transfer dialog
Fix bug in new file transfer widget
Don't write tox_save when unnecessary

Fixes #76 and makes the GUI noticeably faster on slow hard drive.
Merge pull request #80 from F1ynn/fix-widget-win8

Small widget improvements
Add special error message on NXDOMAIN
Remove streches of size 0
Explicitely depend on QtNetwork
Merge pull request #4 from tux3/master

Rebase on upstream