Draft fix for Bug 0b874c344d.  Includes test.
new INST_LMAP_COLLECT, speeds up lmap and eliminates the need for a temp var
fix stack computations for lmap
simplifying: drop early the evaled script
store options early: simplify compiler, reduce stack manipulations
simplify: remove the special case
new test (fails on trunk!), and fix for bug
comments
comments
comments
simplification of the catch compiler and new test
Simplify the coding of the unchain operation.
Improve descriptions of character escapes and ranges in Tcl.n.
Improve output format handlers to cope with added escape for en-dashes.
Refactoring work on the "chain" operation.
Factor out the level offsetting into a final pass.  Let the first
pass of the "chain" operation just stitch things together and count levels.
Making the optimizer pluggable by extensions; please review for committing to trunk
Making the optimizer pluggable by extensions
Big simplification of the bug fix.
merge trunk
[0b874c344d] Fix for nested coroutines ability to stitch together multiple
parts of the CmdFrame chain traversed by [info frame].