Fix wxGTK1 build after wxFont API changes

Implement the new {Get,Set}{FractionalPointSize,NumericWeight} methods.

Also change wxLoadQueryFont() to use wxNativeFontInfo methods as a side
effect, to reduce code duplication and reuse the existing support for
numeric weights and fractional point sizes in wxNativeFontInfo.

include/wx/unix/fontutil.h

@@ -21,10 +21,10 @@
 
 // returns the handle of the nearest available font or 0
 extern wxNativeFont
-wxLoadQueryNearestFont(int pointSize,
+wxLoadQueryNearestFont(float pointSize,
                        wxFontFamily family,
                        wxFontStyle style,
-                       wxFontWeight weight,
+                       int weight,
                        bool underlined,
                        const wxString &facename,
                        wxFontEncoding encoding,