Fixed DLNA is unrealiable, fixes #56

Reusing same HttpClient object helps to increase the performance
webOS will now display media thru DLNA on initial release TVs, with a fallback to tvsimpleviewer, fixes #60
Fixed a typo, does not break any documented, public-facing APIs
Changed some Launcher capability values to match iOS, should not affect APIs
Fixed some issues with capability updates propagating to listener, brought on par with iOS SDK
Fixed bug where no DLNA services were being discovered
ConnectableDevice will no longer recreate its services from JSON, fixes #58
Fix parsing device descriptions with character entities.

The characters() SAX handler may be called multiple times for the
same XML element when there are XML character entities. We need to
append the characters to the current string value.