Portability fixes


extra/yassl/include/buffer.hpp:
  Use assert.h instead of less portable cassert
extra/yassl/include/log.hpp:
  Use stdio.h instead of less portable cstdio
extra/yassl/include/socket_wrapper.hpp:
  Use assert.h instead of less portable cassert
extra/yassl/mySTL/helpers.hpp:
  Use stdlib.h instead of less portable cstdlib
extra/yassl/mySTL/stdexcept.hpp:
  Use string.h instead of less portable cstring
extra/yassl/mySTL/vector.hpp:
  Use assert.h instead of less portable cassert
extra/yassl/src/ssl.cpp:
  Use stdio.h instead of less portable cstdio
extra/yassl/taocrypt/include/block.hpp:
  Use stddef.h instead of less portable cstddef, always use ptrdiff_t instead of less portable std::ptrdiff_t
extra/yassl/taocrypt/include/file.hpp:
  Use stdio.h instead of less portable cstdio
extra/yassl/taocrypt/include/integer.hpp:
  Use string.h instead of less portable cstring
extra/yassl/taocrypt/include/runtime.hpp:
  Use stdlib.h instead of less portable cstdlib
extra/yassl/taocrypt/src/dh.cpp:
  Use math.h instead of less portable cmatch