Handle std::out_of_range correctly on dynamic resolving

Attempting to resolve a dynamic AID username with a number greater than the
size of a uid_t would result in stoi throwing an exception of
std::out_of:range. Now, that exception is defined as returning a NOTFOUND
Version 1.0

Project is now GNUified, using autotools for configuration and compilation.
Header and library existence is checked, configuration files are installed
properly, and everything is looking pretty good...