make JSON data files more git-friendly

[iggu]

I am using mind as a fast to-do manager for my projects and place all it's files into git.
Also I make changes on different machines.
But it's a nightmare to make a merge of mind json since

• it is a single line
• it's structure is not determined

Can you please write json in some deterministic, merge-friendly format? For example

• pretty print the content with indents
• always sort keys
• print all possible keys even if they have no values

Thanks!