Change the way to receive version

- Used git to receive version from tags (see #304)
- Version now displayed when start node (fix #102)

Example:

→ ./bin/node --version
neo-go version 0.44.10-245-g67d5e9f

→ ./bin/node -v
neo-go version 0.44.10-245-g67d5e9f

Makefile

@@ -1,9 +1,10 @@
 BRANCH = "master"
 BUILD_TIME = "$(shell date -u +\"%Y-%m-%dT%H:%M:%SZ\")"
-VERSION = $(shell cat ./VERSION)
 REPONAME = "neo-go"
 NETMODE ?= "privnet"
 
+VERSION ?= "$(shell git describe --tags 2>/dev/null | sed 's/^v//')"
+
 build:
 	@echo "=> Building darwin binary"
 	@go build -i -ldflags "-X github.com/CityOfZion/neo-go/config.Version=${VERSION}-dev -X github.com/CityOfZion/neo-go/config.BuildTime=${BUILD_TIME}" -o ./bin/neo-go ./cli/main.go

cli/main.go

@@ -7,12 +7,14 @@ import (
 	"github.com/CityOfZion/neo-go/cli/smartcontract"
 	"github.com/CityOfZion/neo-go/cli/vm"
 	"github.com/CityOfZion/neo-go/cli/wallet"
+	"github.com/CityOfZion/neo-go/config"
 	"github.com/urfave/cli"
 )
 
 func main() {
 	ctl := cli.NewApp()
 	ctl.Name = "neo-go"
+	ctl.Version = config.Version
 	ctl.Usage = "Official Go client for Neo"
 
 	ctl.Commands = []cli.Command{