WIP: Support for accentuated file paths

This patch fixes the support of accentuated and foreign character support.

Under Linux: First, we force the use of UTF-8 in the main application. Second, we replace all calls to "toLatin1()" by "toLocal8Bit()".

Under Windows: Low level C function cannot be called with UTF-8 strings on Windows. We have to use local system page. As filepath needs to be transfered in UTF-8 through ParaView, we use short file path (8.3 format, generally with a tilde in it) when necessary. Source labels and File Information are correctly presented in their "extended" (long) version (with accents).

This allows to open accentuated files (it was not possible so far) and fixes other issues in the application with accentuated and foreign chars (example: incorrect visualization of a string column for a Text source with Chinese chars in the spreadsheet view).