BUG Empty JSON path should be ignored
BUG Empty JSON path should be ignored

When a JSON response field only contains a "", but a branching structure
which would normally be handled by a return struct is expected, treat
the expected branch as not existing.  This fixes this "" idiom which is
showing up in API v1.3.

herbertjones/mediafire-cpp-sdk,herbertjones/mediafire-cpp-sdk,MediaFire/mediafire-cpp-sdk,herbertjones/mediafire-cpp-sdk,MediaFire/mediafire-cpp-sdk,MediaFire/mediafire-cpp-sdk