Loading foreign libraries at run-time fails to find libexpokit.so

[notmgsk]

In #702 I changed quilc to load libraries at run-time, rather than baking-in the paths to those libraries at compile-time. The benefit of that is that libraries can exist in various places, can be moved around, and we respect LD_LIBRARY_PATH etc. In all cases I tested, everything worked as expected. However, upon trying to build master within docker I found that quilc could not locate libexpokit.so even though it was in the filesystem. Until I've figured out that issue, I'm reverting [584cd3cf, c4275ce0] those commits.