This resolves an issue where estimatesmartfee would return 999
sat/byte instead of 1000, due to floating point loss of precision
Thanks to sipa for suggesting is_integral.
CFeeRate and CTxMemPoolEntry have explicitly defined copy ctors which has the same functionality as the implicit default copy ctors which would have been generated otherwise.
Besides being redundant, it violates the rule of three (see https://en.wikipedia.org/wiki/Rule_of_three_(C%2B%2B_programming) ).
(Of course, the rule of three doesn't -really- cause a resource management issue here, but the reason for that is exactly that there is no need for an explicit copy ctor in the first place since no resources are being managed).
CFeeRate has an explicitly defined copy ctor which has the same functionality as the implicit default copy ctor which would h
ave been generated otherwise.
