Provide test scripts / sanity checking for jplace

[pierrebarbera]

Especially for this early beta phase, it would be great to have a script to check the basic sanity of the output. This could allow the user to ensure some validity, and help me debug problems if the checks are broken for their various data.

[pierrebarbera]

to revisit this: the real goal here is to integrate the kind of tests used in the paper into a CI test, such that large deviations are caught. More tests overall!