keep tag order (no reverse iteration)

Iterate tags in regular instead of reverse order to keep tag ordering (where supported), e.g. pbf.html example:
old:

    way:      {... ,"tags":{"name":"üßé€","highway":"service","access":"private"}, ...
    relation: {... ,"tags":{"type":"route","route":"bus","ref":"123","network":"VVW"}, ...

new (order as defined in test.xml/.pbf):

    way:      {... ,"tags":{"access":"private","highway":"service","name":"üßé€"}, ...
    relation: {... ,"tags":{"network":"VVW","ref":"123","route":"bus","type":"route"}, ...

@marook: Was there a reason to do a reverse iteration? It's not actually wrong as object keys are not guaranteed to be returned in the order added, but they usually are, so I don't see why not to keep that order.