FIX #2049, another problem with the module context on :reload
The previous attempt to fix this (#1873, #1360) left a problem that occurred when the first :load of the program failed (#2049). Now I've implemented a different strategy: between :loads, we remember all the :module commands, and just replay them after a :reload. This is in addition to remembering all the package modules added with :module, which is orthogonal. This approach is simpler than the previous one, and seems to do the right thing in all the cases I could think of. Let's hope this is the last bug in this series...