Add fast scrolling to rom browser

  - Hold down UP or DOWN for continuous (single-item) scrolling
  - Hold down LEFT or RIGHT for fast scrolling
  - Press LB for skip to beginning
  - Press RB for skip to end
Clean-up platform dependant defines, fix compilation on linux.

  - Remove DINGUX_ON_WIN32 in favor of DINGUX
  - Check _GLIBCXX_USE_WCHAR_T to detect if gcc supports wchar
  - Rename Makefile-mingw to Makefile and make it linux friendly
  - Rename Makefile to Makefile.dingux
  - Added STATIC variable to statically link libstdc++ and libgcc,
    run 'make STATIC=1'
Revert back NULL default path for palette browser