Proper way to clear cache and clojure.spec for arguments

[zmaril]

Hello! I accidently ran (scrape seed) as opposed to (scrape (seed)), which failed as expected. This meant that a function was serialized as opposed to a map for the seed I think. I got the following error message I tried to run (scrape (seed)), No reader function for tag function. After a few minutes trying to figure it out, I blew away the cache and things are running fine again. Two questions I have that fall out of this:

1. Is there a proper way to blow away the cache? I'm just starting out, but I can imagine if I had more data, I would have tried to dig in more and save some of it from disappearing.
2. Would you accept a pull request that uses spec to check arguments to functions? Trying to prevent others from making my same mistake. Great library so far, really like the ideas.