Revert "replace .error( with .raiseException( to make it generic (standard error in fancylogger doesn't raise an error)"

This reverts commit b629b60f47c16223828610260ee103359691c16d.
Revert "make sure that agithub python module can be imported without having simplejson installed"

This reverts commit f34440baefd274537e1f8d443ad7f4083c5d9c78.
add robustness against agithub module not being imported because of ImportError, use decorator to check