python-console: Fix globals broken with new JSON library.
simplejson always returns unicode strings. cJSON would return ordinary strings if possible. cPickle.loads() only accepts strings. At present we use pickle version 0 so they should all works as ASCII strings. Higher versions of pickle are not plain ASCII and are likely to break this and so this should be fixed at some point.
Also replaced unconditional exception with one that catches Pickle errors. Not sure the best way to report failures of these functions.