registry initialisers now return the txhash which caller can use to retrieve receipt

* resolver -> common/registrar
  * global registrar name registry interface
  * add Call to resolver backend interface
  * the hashReg and UrlHing contracts now initialised from global registry
  * initialization of contracts uniform
  * improve errors and more econsistent method names
* common/registrar/ethreg: versioned registrar
* integrate new naming and registrar in natspec
* js console api: setGlobalRegistrar, setHashReg, setUrlHint
* js test TestContract uses mining - tests fixed all pass
* eth/backend: allow PoW test mode (small ethash DAG)
* console jsre refers to resolver.abi/addr,
* cmd/geth/contracts.go moved to common/registrar

* resolver -> common/registrar
  * global registrar name registry interface
  * add Call to resolver backend interface
  * the hashReg and UrlHing contracts now initialised from global registry
  * initialization of contracts uniform
  * improve errors and more econsistent method names
* common/registrar/ethreg: versioned registrar
* integrate new naming and registrar in natspec
* js console api: setGlobalRegistrar, setHashReg, setUrlHint
* js test TestContract uses mining - tests fixed all pass
* eth/backend: allow PoW test mode (small ethash DAG)
* console jsre refers to resolver.abi/addr,
* cmd/geth/contracts.go moved to common/registrar

Added some additional backward compatibility code for old receipts

* Reduced maxQueue count
* Added proper deletion past maxQueue limit
* Added cheap stats method to txpool

queueCheck was called for **every** transaction instead of:
1. add all txs
2. check queue

previously

1. add txs[i]
2. check queue
3. if i < len(txs) goto 1.