Some issue fixes

fixed issues #17, #20, #21, #24, #25, #28, #29, #30, #31, #33, #34, #35

Mostly added properties to concepts that were forgotten.
One other major change is that ethon:Uncle is not a subclass of ethon:Block anymore.
For details, please look at the commits. As this is a pre-release of EthOn and things are changing quickly, no full changelog is provided. From version 1.0.0 on, this will change.