Change data file formats to xml or json

[madeso]

The reason is two-fold:

• XML/json is more standard
• We can get better error messages when parsing fails

[madeso]

Stats for the largest file: settings 19k - proto file 26k pretty compact xml (n instead of name, f instead of field, tab instead of 2 spaces etc) 19k - pretty compact json (12k - compact json)

Solution: json is our text format of choice.

[madeso]

json is beeing written and read now. binary file is also written as a backup for when/if the json filing fails