Add tea open (#101)

Fix open default to home page

Improve path join and open with no arg

add labels and milestones

Add tea open

Reviewed-on: https://gitea.com/gitea/tea/pulls/101
Reviewed-by: 6543 <6543@noreply.gitea.io>
Reviewed-by: John Olheiser <john.olheiser@gmail.com>

vendor/github.com/skratchdot/open-golang/open/exec.go

@@ -0,0 +1,18 @@
+// +build !windows,!darwin
+
+package open
+
+import (
+	"os/exec"
+)
+
+// http://sources.debian.net/src/xdg-utils/1.1.0~rc1%2Bgit20111210-7.1/scripts/xdg-open/
+// http://sources.debian.net/src/xdg-utils/1.1.0~rc1%2Bgit20111210-7.1/scripts/xdg-mime/
+
+func open(input string) *exec.Cmd {
+	return exec.Command("xdg-open", input)
+}
+
+func openWith(input string, appName string) *exec.Cmd {
+	return exec.Command(appName, input)
+}