Auto code eval

[lkraider]

Implements the option to eval any string in the json as code by just calling it:

TEST_FILE='''{
    "code": "lambda x: x + 1"
}'''

>>> from jsonsempai import magic
>>> import tester
>>> tester.code(1)
2

Makes the option to outsource your backend programming directly to your API clients/consumers that much easier.