Use string concat rather than [] join
Use string concat rather than [] join

Node's current v8 version is able to perform multiple string concat faster than the older array join.

Test: manipulation - html render (file: jquery.html)
  cheerio x 240 ops/sec ±2.33% (83 runs sampled)
  old x 144 ops/sec ±4.30% (79 runs sampled)
  jsdom x 56.46 ops/sec ±4.27% (62 runs sampled)

Conflicts:
	lib/render.js

cheeriojs/cheerio,cheeriojs/cheerio