Cliffhanger should gracefully hide fields which do not have data

[Nekhelesh Ramananthan]

Currently it seems that when the API does not a return a particular field, the UI sometimes displays an invalid string which is not pretty. We have to lose at these cases.

Steps to reproduce this:

1. Go to Movies Tab
2. Search for the movie "The snow queen"
3. Press the first result
4. In the console, you will notice errors such as "Unable to assign void* to QString".

1. Go to Tv Tab
2. In the Popular carousel, look the tv show "Doctor Who" and click it.
3. In the Tv details page, you will notice the minutes appearing as "undefined minutes", seasons "Qvariant(void*) Seasons" etc etc.

All these should gracefully fall back properly so that the user does not notice this.

[Nekhelesh Ramananthan (nik90)]

Hey arash, I assigned this bug to you since you are more familiar with the json functions which requires a little bit more tweaking to address this bug.

[Arash Badie Modiri (arashbm)]

I don't have slightest idea about why JSON.parse is acting so viewred... it returns QT pointers (void*) instead of undefined.

js:
```
a = JSON.parse("{}")
a.notKey // => undefined
```

Qt:
```
a = JSON.parse("{}")
a.notKey // => Qvariant(void*)
```

[Arash Badie Modiri (arashbm)]

viewred => weird (how did I type that?!)