Don't use an ancient build of tejvm
Bugfix: prevent infinite recursion in gensym

Because clojure.core/gensym is bound to oxcart.core/gensym, oxcart.core/gensym
would recursively call itself until it kills the JVM. This patch grabs the root
of the clojure.core/gensym var so that calling the "reference" gensym is still
possible despite bindings.
Bugfix: Force forms to be a vector

Fixes #17 badly, but it's a fix.
Bugfix: merge-vecs doesn't perserve form order

Fixes #18
Start writing real docs