bson_json_reader_read() now expects that `bson` is uninitialized.
You should only free it if the result was 1.

Use BSON_GNUC_CONST to loader can patch in result instead of function call.
General whitespace cleanup.

fixes assert on win32.

This commit message serves to show how disappointed i am with clang trying
to simply be compatibile with gcc and doing a horrible job of it.

GCC forever.

bson_from_json support