add test for integer in json

[vm-wylbur]

what if the json has an integer?

{
     "plainint": 77
}

I think the str() that's nested in all the calls to tex_escape() should handle it but this seems like overkill. Is there something we can do in tex_escape() to handle it?

[vm-wylbur]

This feature could also check for json values that have backslashes, e.g.,

{ 
    "my_latex_habit": "23\%" 
}