Added check on content-type in http error handling

[simlay]

This is for #55

I'll be honest, my Node isn't perfect I'm all for a cleaner solution if suggested.

[jorilallo]

Thanks, this looks great. I'll need to test this as we're lacking test coverage for these tests cases so will merge later

[simlay]

I'm all for writing some tests.

My only issue is that the nock http implementation doesn't have the getHeaders on a response object. Though, I could be using it wrong.

@jorilallo Do you have any suggestions on this?

[CjS77]

I would prefer still keeping the actual error message here. Return response.body rather than masking it with 'InternalServerError'

Alternatively,

var errorBody;
try { 
    errorBody = _parseError(JSON.parse(response.body));
 } catch (ex) {
   errorBody = { id: -1, message: response.body };
}
...

[jorilallo]

@simlay thanks for raising this. @CjS77 actually pushed a fix for this so I'll close this one. Sorry for the long turnaround time