pretty-printer for symbols.
dbg: don't print so many "stack" entries.
gfx: make 'Pre' return an error.
improved error detection in 'AddWatch'.
improved error messages, stopping on errors, etc.

generally just making things easier to debug/figure out what's
going on.
clean up command line opts, drop some code.
fix a bunch of types tests.

make sure the test program vars are unsigned.  check for signed
before unsigned, since e.g. "int64" is part of "uint64" and thus
we should check the more-specific version first.  update tests to
expect unsigned vars, as per the test program changes.
minor cleanups, mostly deleting dead code.

also don't export PROT_*, rename 'StackReader' to 'FuncABI'.
rename: newmallocs -> supervise
rename malloctrace -> supervise
make things more debuggable with more verbose errors.
add a 'minsize' command line parameter, + to globals.

used as a threshold on allocations, so that we don't look at *all*
of them.
add experimental test for already-existing breakpoints.

to be sure we're not double-inserting something.  not sure if this
should stay.  i think if there are two BPs to the same place,
everything should be okay as long as they are "unwrapped"
(Unbreak'd) in a FIFO order.
vis2d impl.  must have forgotten to add this the other day.
allow RetAddrMid to fail w/o halting execution.

so that we can just try alternate methods for figuring out the
return address.