Xpath scraping from URL (#285)

* Add xpath performer and scene scraping

* Add studio scraping

* Refactor code

* Fix compile error

* Don't overwrite performer URL during a scrape

vendor/github.com/antchfx/xpath/func_pre_go110.go

@@ -0,0 +1,15 @@
+// +build !go1.10
+
+package xpath
+
+import "math"
+
+// math.Round() is supported by Go 1.10+,
+// This method just compatible for version <1.10.
+// https://github.com/golang/go/issues/20100
+func round(f float64) int {
+	if math.Abs(f) < 0.5 {
+		return 0
+	}
+	return int(f + math.Copysign(0.5, f))
+}