Basic RPC and CLI Queries (#77)

- Adds ethermint query command (`emintcli query ethermint <query>`)
    - Supports block number, storage, code, balance lookups
- Implements RPC API methods `eth_blockNumber`, `eth_getStorageAt`, `eth_getBalance`, and `eth_getCode`
- Adds tester utility for RPC calls
    - Adheres to go test format, but should not be run with regular suite
    - Requires daemon and RPC server to be running
    - Excluded from `make test`, available with `make test-rpc`
- Implemented AppModule interface and added EVM module to app
    - Required for routing
- Implements `InitGenesis` (`x/evm/genesis.go`) and stubs `ExportGenesis`
- Modifies GenesisAccount to match expected format

x/evm/types/key.go

@@ -6,4 +6,6 @@ const (
 
 	EvmStoreKey = "evmstore"
 	EvmCodeKey  = "evmcode"
+
+	RouterKey = ModuleName
 )

x/evm/types/querier.go

@@ -0,0 +1,46 @@
+package types
+
+import (
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"math/big"
+)
+
+type QueryResProtocolVersion struct {
+	Version string `json:"result"`
+}
+
+func (q QueryResProtocolVersion) String() string {
+	return q.Version
+}
+
+type QueryResBalance struct {
+	Balance *hexutil.Big `json:"result"`
+}
+
+func (q QueryResBalance) String() string {
+	return q.Balance.String()
+}
+
+type QueryResBlockNumber struct {
+	Number *big.Int `json:"result"`
+}
+
+func (q QueryResBlockNumber) String() string {
+	return q.Number.String()
+}
+
+type QueryResStorage struct {
+	Value []byte `json:"value"`
+}
+
+func (q QueryResStorage) String() string {
+	return string(q.Value)
+}
+
+type QueryResCode struct {
+	Code []byte
+}
+
+func (q QueryResCode) String() string {
+	return string(q.Code)
+}