None of these are very serious, and are leaks in objects that are
created at most one time.
In most cases this means properly using the QObject parent hierarchy,
except for BanTablePriv/PeerTablePriv which are not QObject,
so use a std::unique_ptr instead.
- add missing NULL pointer checks
- add better comments and reorder some code in rpcconsole.cpp
- remove unneeded leftovers in bantable.cpp
- update bantable column sizes to prevent cutting of banned until
isle2983