strengthened induction rule; clarified some proofs

limit the number of generated SMT monomorphization instances (in addition to the existing monomorphization limit which does not prevent seemingly infinite loops); updated SMT certificate

more explicit errors to inform users about problems related to SMT solvers; fall back to remote SMT solver (if local version does not exist); extend the Z3 proof parser to accommodate for slight changes introduced by Z3 2.18

more explicit exit due to failed etc/settings -- normally return code 0=true and 1=false could be tolerated, but bash syntax errors also return 1;

eliminated somewhat obsolete warning -- former "$HOME/Isabelle" vs. "$HOME/isabelle" no longer exist;

tuned;