added RPC start/stop support

cmd/geth/js.go

cmd/geth/js_test.go

cmd/utils/flags.go

rpc/api/admin.go

rpc/api/admin_args.go

rpc/api/admin_js.go

rpc/api/api.go

rpc/api/args.go

rpc/api/args_test.go

rpc/api/db.go

rpc/api/debug.go

rpc/api/eth.go

rpc/api/mergedapi.go

rpc/api/mergedapi_js.go

rpc/api/miner.go

rpc/api/net.go

rpc/api/personal.go

rpc/api/shh.go

rpc/api/txpool.go

rpc/api/utils.go