use cwd for link default

cli.js

@@ -17,6 +17,7 @@ function run () {
  var db = dat({home: args.home})
  if (firstArg === 'link') {
    var dirs = args._.slice(1)
    if (dirs.length === 0) dirs = process.cwd()
    db.add(dirs, function (err, link) {
      if (err) throw err
      db.joinTcpSwarm(link, function (_err, link, port, close) {

tests/link.js

@@ -8,11 +8,25 @@ var path = require('path')
var dat = path.resolve(path.join(__dirname, '..', 'cli.js'))
var dat1 = path.join(__dirname, 'fixtures')
var tmp = os.tmpdir()
var dat1link

test('prints link', function (t) {
  var st = spawn(t, dat + ' link ' + dat1 + ' --home=' + tmp)
  st.stdout.match(function (output) {
    t.equal(output.length, 71, 'version is length 71: dat:// + 64 char hash + newline')
    dat1link = output.toString()
    st.kill()
    return true
  })
  st.stderr.empty()
  st.end()
})

test('link with no args defaults to cwd', function (t) {
  var st = spawn(t, dat + ' link --home=' + tmp, {cwd: dat1})
  st.stdout.match(function (output) {
    t.equal(output.length, 71, 'version is length 71: dat:// + 64 char hash + newline')
    t.equal(output.toString(), dat1link, 'links match')
    st.kill()
    return true
  })