Log Message:
Update devel/libbson to 1.4.0.

- bson_reader_reset seeks to the beginning of a BSON buffer.
- bson_steal efficiently transfers contents from one bson_t to
  another.
- Fix Windows compile error with BSON_EXTRA_ALIGN disabled.
- Potential buffer overrun in bson_strndup.
- bson_oid_to_string optimization for MS Visual Studio
- bson_oid_is_valid accepts uppercase hex characters.
- bson_json_reader_read aborted on some invalid Extended JSON
  documents.
- All man page names now begin with "bson_" to avoid install
  conflicts.
- Error messages sometimes truncated at 63 chars.