Prevent null_ptr crashes.
DropJob: don't touch iterator after erasing element

Also drops a redundant condition
Catch exception by reference
Remove dead code

Q_ASSERT(Compiler isn't a total moron);
Servent: Fix IP protocol version distinction

Uwe failed at C&P!
Reduce variable scopes

Also reduces some boolean logic verbosity.
Remove break after return, it is redundant
JSResolver: read duration as signed integer
JSResolver: avoid unnecessary calls, simplify logic, consts
Resolvers: Remove useless assignments
JSResolverHelper: Fix typo in accountId() function name
Avoid copying of constructor results
JSResolverHelper: Make use of helper functions
JSResolverHelper: comparison function: pass QVariant by reference