regexp: fix utf8_setunicode -> utf8_getchars

Signed-off-by: Steve Bennett <steveb@workware.net.au>
Consider scripts with trailing backslash as unfinished

From the interactive prompt.

Reported-by: Sergei Gavrikov <sergei.gavrikov@gmail.com>
Signed-off-by: Steve Bennett <steveb@workware.net.au>
Properly respect backslashes in comments

Reported-by: Sergei Gavrikov <sergei.gavrikov@gmail.com>
Signed-off-by: Steve Bennett <steveb@workware.net.au>
Enhance examples/jtclsh.tcl

Now uses [info complete] to support continuations.
Includes error code indication

Signed-off-by: Steve Bennett <steveb@workware.net.au>
Add titles to recent regression tests

Reported-by: Sergei Gavrikov <sergei.gavrikov@gmail.com>
Signed-off-by: Steve Bennett <steveb@workware.net.au>