Remove FashionVictim DEMARK or peg econ-ark dependency to 0.10.2

[sbenthall]

The FashionVictim DEMARK imports code from HARK:

https://github.com/econ-ark/DemARK/blob/master/notebooks/Fashion-Victim-Model.py#L52

After this, it appears to execute the exact same code that is in the Fashion-Victim-Model main() method:
https://github.com/econ-ark/DemARK/blob/master/notebooks/Fashion-Victim-Model.py#L123
https://github.com/econ-ark/HARK/blob/master/HARK/FashionVictim/FashionVictimModel.py#L414

In other words, this DEMARK is just a duplicate of what's in HARK, with some copy-and-pasted code.

FashionVictim is slated to be taken out of the HARK source library and into a HARK examples/ directory.
econ-ark/HARK#440

It has been argued that since FashionVictim is really a kind of tutorial documentation, not material for economics students, it's better for it to be in examples/ than to be a DemARK.

Either:

• The DemARK should be removed, or,
• the DemARK econ-ark dependency should be pegged to version 0.10.2 so this DemARK can keep depending on HARK.

If we decide on the latter for some reason, I hope we put some thought into how to design this better to avoid code duplication across repositories.

[llorracc]

Let's make FashionVictim an "example" notebook, and remove it from the DemARK.

[llorracc]

@sbenthall will integrate this with econ-ark/HARK#446

[sbenthall]

Fixed with e4a30aa#diff-c2365e874ecb861a659e5215ff17c338