Add tool on the Tools screen for fixing issues with conversions, like & and such

[cquencer]

Reported by Svein W.

There are some larger differences in the way Ninjaboard and other boards like phpBB3 stores text.
This needs to be solved by adding a tool for it, as this may change depending on the version and software as well as the configuration.

Original ticket:
When converting from phpBB3, the & character in forum names became

&