All source files now use UTF8 encoding. Second try.

Files in the source tree have full Babylon of encodings in comments

- UTF8
- Win1251
- KOI8 (wal_tmpls.h)
- Combination of UTF8 and Win1251 in the same file (sftpdlg.cpp, swl_winbase.h, swl_wincore.h, swl_wincoreUX.cpp)

All the files now use UTF8. Note that the word 'бля' is now readable there.

This is second attempt to straighten out the encodings. Previous one was performed on a source that was behind HEAD.