Allow returning different JSON RPC error codes depending on error type

Added to git modules

* Added a GetTransaction to XEth
* Implemented the `eth_getTransactionByHash` RPC method

* Add transaction to extra database after a successful block process

Move MakeName to ethutil

dbdd0f8 update test script for python
29dced2 add failing python test
5b7ebb9 OOG or 1024 depth level fail
3f58fd8 run OOG at tx level with to high value for call
39d8595 run OOG and too high value for call/callcode
55fbf95 run OOG and too high value for call/callcode
8856bfb add callCreateCallCode test file
d2da29e check value when doing callcode
129a464 suicide and storage refund tests with and without storage
6aa5e29 suicide and storage refund tests
fff323d python fails
963648b python callcode fail
31ce83a python big memory fail
531bc36 add memory stress test using return
b7021c7 renaming
959ff59 vm input limit tests
1c3741f update blockchain tests with new uncle reward rule

git-subtree-dir: tests/files
git-subtree-split: dbdd0f829dea8aa053159707caf353d83bf5be0f

miner: provide coinbase when starting the miner

This error can no longer be returned from eth.New.

This avoids having to query the coinbase when creating the miner, which
in turn eliminates the dreaded startup error when no accounts are set
up. Later, this will also allow us to simply restart the miner when the
user picks a different coinbase.

This causes a lot of changes in other packages. These are included in
this commit because they're impossible to separate.