Sanitized the number casting operators

Using stoi for uint32_t would result in it throwing if the number is between
the limit of int32_t and uint32_t. The same would probably count for the 64
ones on a 32 bit platform, forcing them to use long long 'should' fix this issue.
Merge branch 'master' of github.com:CopernicaMarketingSoftware/REACT-CPP-MYSQL