Safely handle project.clj's that use read-eval

[danielcompton]

https://github.com/clojure-emacs/orchard/blob/ce0d586905c53b596679b147806b921f3285ef6e/project.clj#L45-L47 uses #=(eval which throws an error:

[{:type java.lang.RuntimeException
   :message EvalReader not allowed when *read-eval* is false.
   :at [clojure.lang.Util runtimeException Util.java 221]}]

It would be good to be able to gracefully handle these kinds of failures and return nil in that place in the project map, instead of throwing entirely.