Create and immediately destroy a context when initialising the SMJS
document scripting module, because SMJS crashes on exit if there has
been no context created since it started, which is the case if one does
not load any documents.
Replace the ECMAScript module initialisation and de-initialisation
routines that wrapped the SMJS and SEE module initialisation and
de-initialisation routines by having the module system call the SMJS
and SEE routines its own darned self.
