Implement cancel of chmod of many files.

Implement cancel of chmod of many files.

What steps will reproduce the problem?
1. Selected many files (12000 in my case).
2. Ctrl+x c (chmod) - changed mode to desired one.
3. MC started to change file modes but failed, it shows error popup
"Cannot chmod ... Operation not permitted (1)" for every file and waits
for a keypress.
MC shows error for every file in a list (12000 times), there is no
chance to cancel the whole operation, only to press any key 12000 times
or to kill MC.

The solution: implement error message with follow buttons:
"Ignore" -- ignore current error;
"Ignore all" -- ignore current error, try chmod of other selected files,
and ignore all following errors;
"Retry" -- retry chmod operation;
"Cancel" -- cancel chmod operation immediately.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>