p2: rename global Env to %ENV
p2: support -e"bla", set globals $P2::execmode, $P2::verbose, $P2::interactive for introspection

Besides -e "" you can do also now -e"".
Fix interactive with -e.
Unsure how the access the globals yet.
verbose should later be used as -D? debugflags, to do run-time -Dp, -Dpv (ie -DYY_DEBUG)
  or -DJ (-DJIT_DEBUG)