Revise TclNREvalObjv so that pre-resolution of the Command by a caller
does not force suppression of exception handling.  Let those be separable
demands.  Aim is to bring TclObjInvoke*() into the fold.
merge trunk
New internal routine TclNRInvoke() - NR-enabled path through the machinery
behind invokehidden commands.
More revisions let multi-interp test case work, but at cost of panics
and segfaults.  Pushing the NRE-envelope.
More progress.  NR-enable [interp] and [$slave], completely with
invokehidden subcommand.  Test suite passes with no errors.
merge trunk
Possible improvement in light of [86ceb4e2b6].
merge trunk
merge trunk
merge trunk
merge trunk
merge trunk
Revise execution trace handling to take account of the new reality in
Tcl 8.6 that callers can pre-resolve a cmdPtr for us.  In that case
a re-resolution in the form of another command name lookup isn't the right
thing.
define tests for this bug; no fix yet
merge trunk
merge trunk
merge trunk
merge trunk
Unbreak doc; the apropos index entry *must* be one line.
merge trunk