Issue description

The datadir field on the debug window displays incorrectly if the profile folder name is accented.

How to reproduce

1. Create a profile with accented profile folder name (àèìòùáéíóú)
2. Run bitcoin core with the default datadir
3. Go to the debug window and look at the datadir field

Expected behaviour

The datadir folder path should display correctly.

Actual behaviour

Accented characters display as a unknown character question mark.

Screenshots

Confirmed affected versions

The bug has been tested on the following implementations:

• v0.13.1 from source cross-compiled for Windows x64 on a Ubuntu 14.04 enviroment
• 0.13.0 official Windows x64 binary

Additional debug info

Copying and pasting the text into a program that is known to support accented characters (Such as Notepad++) still displays unknown character symbols.