Color profiles not loaded on Windows

Reproduced on Windows XP (32-bit) with lp:inkscape/0.92.x rev. 15214.
Not reproduced on Xubuntu 16.04, lp:inkscape/0.92.x rev. 15214 and lp:inkscape rev. 15273.

On Windows XP, the profiles linked to a document are listed in the Documents properties and F&S dialogs, but can't be used. It seems to be due to bug in src/uri.cpp (called from src/color-profile.cpp, ColorProfile::set method).

The document docbase is "C:\Documents and Settings\nicolas\Bureau\SVG\profiletest.svg" and xlink:href="C:\WINDOWS\System32\spool\DRIVERS\COLOR\is330.icm" (only one profile to keep the example as simple as possible).

In ColorProfile::set:
1. "g_uri_escape_string" returns an escaped path for the profile:
"C:%5CWINDOWS%5CSystem32%5Cspool%5CDRIVERS%5CCOLOR%5Cis330.icm".
2. In "URI::from_native_filename", the path is then turned into an uri with "g_filename_to_uri":
"file:///C:/Documents%20and%20Settings/nicolas/Bureau/SVG/profiletest.svg"
and then initialized as an URI object.
3. "URI::getFullPath" is called for the docbase URI object, and itself calls "_impl->getPath()" that returns:
"/C:/Documents and Settings/nicolas/Bureau/SVG/profiletest.svg"
4. "URI::getFullPath" tests the path, and as it's an invalid path, clears it.
5. Another URI object is created for the profile path. "_impl->getPath()" returns:
"\WINDOWS\System32\spool\DRIVERS\COLOR\is330.icm"
Invalid again, the path is clears.
6. "cmsOpenProfileFromFile" tries to open an empty path, and fails, but an empty (and completely useless) color profile is created with a correct name anyways.

Replacing:
gchar* fullname = g_uri_unescape_string(fullpath.c_str(), "");
with:
gchar* fullname = g_uri_unescape_string(escaped, "");
fixes the issue on Windows XP, with profiles linked as absolute path. But of course, it would be better to fix the issue in the URI creation.