Broken autocompletion in mcedit

[andrew_b]

Two testcases.

1. Locale is UTF-8, file is in KOI8-R:

   эъйцукен
   эъфывапр
   
   эъ<esc-tab here>
   

Result: no completion list, no completion.

1. Locale is KOI8-R, file is in UTF-8:

   эъйцукен
   эъфывапр
   
   эъ<esc-tab here>
   

Select эъйцукен in completion list.

Result: эъукен -- two chars in completion position are missed.