clean up solution

MSVC/.gitignore

MSVC/contrib/src/fetch_and_patch.bat

MSVC/contrib/src/gmp/fetch_and_patch.bat

MSVC/contrib/src/gmp/gmp-uwp.patch

MSVC/contrib/src/gnutls/fetch_and_patch.bat

MSVC/contrib/src/gnutls/gnutls-no-egd.patch

MSVC/contrib/src/gnutls/gnutls-uwp.patch

MSVC/contrib/src/gnutls/read-file-limits.h.patch

MSVC/contrib/src/iconv/fetch_and_patch.bat

MSVC/contrib/src/iconv/libiconv-uwp.patch

MSVC/contrib/src/msgpack/fetch_and_patch.bat

MSVC/contrib/src/msgpack/msgpack-uwp.patch

MSVC/contrib/src/nettle/fetch_and_patch.bat

MSVC/contrib/src/nettle/nettle-uwp.patch

MSVC/contrib/src/zlib/fetch_and_patch.bat

MSVC/contrib/src/zlib/zlib-uwp.patch

MSVC/dhtchat.vcxproj

MSVC/dhtnode.vcxproj

MSVC/dhtscanner.vcxproj

MSVC/opendht.vcxproj