- Port Wine's WideCharToMultiByte implementation for conversion to a codepage to...

- Port Wine's WideCharToMultiByte implementation for conversion to a codepage to ReactOS. (with comments :-))
  It adds support for DefaultChar, UsedDefaultChar and the flag WC_NO_BEST_FIT_CHARS.
  WC_COMPOSITECHECK is also supported by the Wine implementation, but I don't have an idea how to port it to ReactOS, as we don't seem to have composition tables. I left FIXME's for this flag in the appropriate blocks, this is why some of the code might look badly structured/unoptimized at the moment.
  As we completely rely on the NLS tables for the conversion now, this commit might trigger some bugs there. I already found out that the CP950 table doesn't map Unicode 0 back to MultiByte 0 (but 254), using Windows' c_950.nls it works correctly. Other tables could be buggy as well, c_1252.nls worked flawlessy for me though.
- Added comments to the CPTABLEINFO structure based on documentation from http://www.ping.uio.no/~ovehk/nls/

svn path=/trunk/; revision=34426