Also find lib-prefixed libraries under Windows

For lzma and iconv.
Force re-checking *all* libs on CXXFLAGS changes
Add support for the progress bar under Windows
Add support for color output under Windows
Fix MSVC 9 build
Always use 64-bit time values internally

And warn if a truncating conversion is performed.
Force 64-bit time values on Windows

MSVC already always uses a 64-bit time_t, but 32-bit MinGW doesn't.
Don't change the default text color under Windows
Improve error message if input file is a directory
Fix MSVC 9.0 warnings
Add a workaround for mixed iconv versions on OS X