During an additional evaluation triggered by an automated module
handling mechanism, ensure warning and error messages are reported under
the message block of the main evaluation.
Add a 'recordtop' argument to the reportWarning and reportError
procedures in order to indicate that the message should be recorded
under the top-level message block instead of the currently active
message block.
Fixes#252.
Add a cookbook section in the documentation and port there the 3
pre-existing recipes: inhibit-report-info, top-priority-values and
unload-firstly-loaded.
Move the examples files of these recipes from contrib/cookbook to
doc/example directory.
