Remove duplicate symbol "assert"

[caitp]

Fixes #14

[caitp]

This is just a first attempt at this, it's probably still broken

[caitp]

So, this is still broken because tests, and possibly more of the library, need to be updated to match the current watchtower.

@EisenbergEffect can you help me with this tomorrow? I think that this kind of break is something that's likely to continue to occur in the modular architecture, too

[EisenbergEffect]

I can take care of it. I'm wondering...should expressionist be dependent on watchtower? Or should we move the WatchParser class into watchtower and reverse the dependency?

[caitp]

the way it is now, theoretically watchtower should be agnostic about expression languages, so I think that's the main reason why watchparser lives in expressionist. But it's true that it is awkward and will likely lead to breaking.

Lets talk to Miško about it and see what he thinks (in a few days)