eth_getBlockByNumber impl

[austinabell]

• Completes Implement eth_getBlockByNumber #41

Notes:

• Tx hashes are hashes of the amino encoded tx (since that is how they are referenced by getting transaction by hash through tendermint)
• Will wait to include logs bloom filter once similar logic is completed with Implement eth_getLogs #55
• Gas usage for block cannot be calculated when txs are not populated, will look into saving gasUsed by block later if necessary

To test:

1. Run the Ethermint node:

make install 
rm -rf ~/.emint*
emintd init moniker --chain-id 3
emintcli config chain-id 3
emintcli config output json
emintcli config indent true
emintcli config trust-node true
emintcli keys add austin
testpass
testpass
emintcli emintkeys add austineth
testpass
testpass
emintd add-genesis-account $(emintcli keys show austin -a) 1000photon,100000000stake
emintd add-genesis-account $(emintcli emintkeys show austineth -a) 100000000photon,100000000stake
emintd gentx --name austin
testpass
emintd collect-gentxs
emintd validate-genesis
emintd start --pruning=nothing --rpc.unsafe --log_level "main:info,state:info,mempool:info,*:error"

2. Start rest server with unlocked key to send tx to test functionality

emintcli rest-server --laddr "tcp://localhost:8545" --unlock-key austineth

3. Send a transaction to test all values in a block:

curl -X POST --data '{"jsonrpc":"2.0","method":"eth_sendTransaction","params":[{"from":"0x'$(echo -n $(emintcli emintkeys show austineth -w))'","to":"0xd46e8dd67c5d32be8058bb8eb970870f07244567","gas":"0x76c0","gasPrice":"0x12","value":"0x20","data":"0xd46e8dd67c5d32be8d46e8dd67c5d32be8058bb8eb970870f072445675058bb8eb970870f072445675"}],"id":1}' -H "Content-Type: application/json" http://localhost:8545/rpc

Retrieve block based on block transaction(s) processed (replace 0x2 with block number):

curl -X POST --data '{"jsonrpc":"2.0","method":"eth_getBlockByNumber","params":["0x2", false],"id":1}' -H "Content-Type: application/json" http://localhost:8545/rpc
## Response: {"jsonrpc":"2.0","id":1,"result":{"difficulty":null,"extraData":null,"gasLimit":"0xffffffffffffffff","gasUsed":null,"hash":"048091BC7DDC283F77BFBF91D73C44DA58C3DF8A9CBC867405D8B7F3DAADA22F","logsBloom":"","miner":"13C1A823D673ACAE1F5B03266B06E210E73DC650840F383DD72AB1152BF78AD3","nonce":null,"number":2,"parentHash":"97CB044D3F23C4F2546C40C479D91B62CBAA8FC0A0245522134A9F0B350DBE5B","sha3Uncles":null,"size":"0x34f","stateRoot":"0CC2CBC2FB4F0F610C81BD4FC6970B6AF691795A9460A6B2CC0D1B63BBB101DD","timestamp":"0x5d892e6d","totalDifficulty":null,"transactions":["0x51271e6720e1e87c8fbbe0ed83f979798549f56d29dabde6382fdab1111294de"],"transactionsRoot":"3A7890603A4AD8DB38E5F4E6F2F35069A688FFE1FA0F5AFB74150A79C84A0FF8","uncles":null}}

and set the full tx flag to test that functionality:

curl -X POST --data '{"jsonrpc":"2.0","method":"eth_getBlockByNumber","params":["0x2", true],"id":1}' -H "Content-Type: application/json" http://localhost:8545/rpc
## Response: {"jsonrpc":"2.0","id":1,"result":{"difficulty":null,"extraData":null,"gasLimit":"0xffffffffffffffff","gasUsed":547200,"hash":"048091BC7DDC283F77BFBF91D73C44DA58C3DF8A9CBC867405D8B7F3DAADA22F","logsBloom":"","miner":"13C1A823D673ACAE1F5B03266B06E210E73DC650840F383DD72AB1152BF78AD3","nonce":null,"number":2,"parentHash":"97CB044D3F23C4F2546C40C479D91B62CBAA8FC0A0245522134A9F0B350DBE5B","sha3Uncles":null,"size":"0x34f","stateRoot":"0CC2CBC2FB4F0F610C81BD4FC6970B6AF691795A9460A6B2CC0D1B63BBB101DD","timestamp":"0x5d892e6d","totalDifficulty":null,"transactions":[{"blockHash":"0x048091bc7ddc283f77bfbf91d73c44da58c3df8a9cbc867405d8b7f3daada22f","blockNumber":"0x2","from":"0x4c98655e693f7d1ba2c43f38720c99201a1c7498","gas":"0x76c0","gasPrice":"0x12","hash":"0x4db86f1646925f36f06257e1f57c43cd6947f283e93e18d00441178f7ce2d4eb","input":"0xd46e8dd67c5d32be8d46e8dd67c5d32be8058bb8eb970870f072445675058bb8eb970870f072445675","nonce":"0x0","to":"0xd46e8dd67c5d32be8058bb8eb970870f07244567","transactionIndex":"0x0","value":"0x20","v":"0x2a","r":"0xb683b308cc7f8d91b91f7f73dcc87e3f2fde625727b06b523eed3164c705e0ef","s":"0x566c420cdd54accb2447e8dbd1836c91f3018dc96fffd887d3f4041b8f3c44ee"}],"transactionsRoot":"3A7890603A4AD8DB38E5F4E6F2F35069A688FFE1FA0F5AFB74150A79C84A0FF8","uncles":null}}