Accept reports format: JSON (instead of form-urlencoded)

[chrisblech]

The last version of my app sends ACRA reports data as JSON (reportType = rg.acra.sender.HttpSender.Type.JSON), as this was recommended by Acralyzer.

Now I wanted to switch to ACRAViz (much better performance!) and set up an proxy that hands all reports to the new endpoint - but ACRAViz doesn't show any data, because it can't parse the incoming JSON...

see: https://github.com/ACRA/acra/wiki/Report-Destinations#data-encoding-formjson

Since ACRA v4.5.0, you have the option to send reports data encoded as a detailed JSON tree structure. You can see here 2 examples of the data generated with the default set of ReportFields.