tvOS support

[jakubknejzlik]

I've updated podspec file and added support for specifying NSSearchPathDirectory for method storeURLForName. The reason is that app cannot access Documents directory on real device, and CachesDirectory must be used.

[jakubknejzlik]

Another approach should be recognizing the os

something like:

var searchPath = .DocumentDirectory
#if os(tvOS)
    searchPath = .CachesDirectory
#endif

sounds easier in some cases :)

[tadija]

Hello @jakubknejzlik, thanks for this. I merged it and implemented another approach which you suggested, I think it's better like that.