libdatrie 0.2.13 Released

• Fix wrong key listing in byte trie
  (Issue #9, Thanks @legale for the report.)
• Fix cross-compiling issue caused by AC_FUNC_MALLOC
  (Issue #11, Thanks @vmchale for the report.)
• Fix isspace() arg problem on NetBSD.
  (Personal mail, Thanks Sean for the report;
  PR #8, Thanks @obache for an independent pull request.)
• Fix some documentations.
• Really use TRIE_CHAR_TERM in TrieChar string termination.
  Changing TRIE_CHAR_TERM definition now won't break the code.
• Fix Windows build issue by avoiding <unistd.h> include.
  (Partially addressing PR #15, Thanks @fanc999 for first raising this.)
• [New APIs] Add serialization of the trie into memory buffer.
  (PR #12, Thanks @KOLANICH for the contribution.)